Abstracts From the 2022 International Sport + Exercise Nutrition Conference

in International Journal of Sport Nutrition and Exercise Metabolism

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Exploring the Role of Peanuts in Enhancing Healthy Weight Gain in Athletic Individuals

Sanchez A1, J Reynolds1, E Marinik1, B Davy1, G Hunter2, DE Larson-Meyer1

1Department of Human Nutrition, Foods, and Exercise, Virginia Tech, USA

2Department of Nutrition Sciences, University of Alabama at Birmingham, USA

Many athletes and military personnel desire weight gain primarily as lean mass to improve performance and effectiveness in sport/military endeavours. These athletes are commonly encouraged to increase energy intake by ∼500 kcal/day with an emphasis on adequate protein and carbohydrate, and judicious inclusion of healthy fat-containing energy-dense foods including peanuts/peanut butter along with rigorous resistance training. Little, however, is known about the efficacy of such regimens. This study evaluated the effect of a 10-week diet and exercise regimen designed to promote healthy weight gain. This included increasing energy intake by 500 additional kcal/day (above weight maintenance diet) through daily provision of either peanut-based whole foods/snacks (peanut group) or a similar, high-carbohydrate, peanut-free snack (carbohydrate group) along with a supervised resistance training regimen (3 days/week for 60–120 minutes targeting the major muscles). Athletes (N=28; active-duty Navy, Army National Guard, Marine Corps Reserve, collegiate, club, firefighter, and recreational; previous resistance training experience; 25 ± 6 y) were randomly assigned to the peanut or carbohydrate group. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) at baseline, 3-weeks, 7-weeks, and post-intervention. Results demonstrated a total body mass (TBM) gain of 2.2 ± 1.3 kg (range of −0.9 to 4.4 kg) with 1.5 ± 1.1 kg (range of −0.5 to 3.4 kg) as lean body mass (LBM) after 10 weeks. The peanut group (n=12; 29 ± 7 y; 8 males, 4 females) gained less TBM than the carbohydrate group (n =16; 23 ± 3 y; 9 males, 7 females) (1.5 ± 1.1 kg vs 2.7 ± 1.2 kg, p=0.01) and less LBM (0.96 ± 0.94 kg vs 1.9 ± 1.0 kg, p=0.023) than the carbohydrate group. The age of the groups was different (p=0.006). Males (n=17) and females (n=11) had a TBM gain of 2.0 ± 1.4 kg and 2.5 ± 1.1 kg (p=0.355) with a LBM gain of 1.3 ± 1.1 kg and 1.7 ± 0.95 kg (p=0.374), respectively. These results suggest that the addition of 500 kcal/day from whole foods/snacks in combination with a rigorous resistance training program promotes a similar weight gain of ∼0.22 kg/week, primarily as LBM, over 10 weeks in both male and female athletes. However, age and/or snack macronutrient content may impact the effectiveness of this regimen.

Sport Specific Stress is Associated with Eating Attitudes and Metabolic Compensation in Collegiate Female and Male Endurance Athletes

Lundstrom EA1, MJ De Souza2, P Kuruppumullage Don3, NI Williams4

1Department of Kinesiology, Penn State University, United States of America

2Department of Kinesiology, Penn State University, United States of America

3Department of Statistics, Penn State University, United States of America

4Department of Kinesiology, Penn State University, United States of America

A competitive sport season represents a multidimensional stressor where physical and psychological stress may render an athlete susceptible to chronic energy deficiency (ED). Downstream effects of chronic ED can include a reduction in the ratio of measured-to-predicted resting metabolic rate (RMR), a signal of energy repartitioning. Links between ED and metabolic adaptation have been established in athletes, a plausible pathway linking stress, eating attitudes, metabolic adaptation has not been explored. Test the hypothesis that total and/or sport-specific stress is associated with eating attitudes and metabolic compensation in swimmers and runners (18–22 y) at different phases of a competitive season, we performed two studies. Study 1: Cross-sectional; 25 swimmers (14 female, 11 male); engaging in heavy training during peak season (PEAK). Study 2: Longitudinal; 25 runners (female); across pre-season (PRE) and off-season (POST). Measures: stress (RESTQ-52), eating attitudes (cognitive restraint (CR), drive for thinness (DT)/leanness (DL)/muscularity (DM), and body dissatisfaction (BD)), metabolism (RMR, TT3). In PRE, RESTQ-52 Sport-Specific and Total Stress were negatively correlated with RMR ratio (R=-.58; p< .05, R=-.48; p< .05, respectively). CR was negatively related to RMR ratio (R=-.55; p< .05). During PEAK, Sport Specific and Total Stress were negatively correlated with RMR ratio (R=-.64; p< .05; R=-.46; p< .05, respectively). DM was negatively related to RMR ratio (R=-.40; p=.05) and positively related to Sport Specific Stress (R=.55; p< .05). During POST, there was no relation between RMR ratio and Sport Specific Stress. BD was positively related to General (R=.52; p< .05) and Total Stress (R=.49; p< .05) Across the season in runners, there was a change in stress measures from PRE-to-POST with highest reported General, Sport-Specific and Total Stress during PRE (p< .05) versus POST. ΔRMR ratio was negatively related to ΔSport Specific Stress (R=-.41; p< .05), and ΔRMR/FFM was negatively related to ΔCR. Associations between stress, eating attitudes, and metabolic compensation in two groups of endurance athletes during PRE and PEAK season suggest that during phases of heavy training, unfavourable metabolic changes may be linked to upstream eating attitudes associated with sport stressors.

Mindfulness in Eating Is a Significant Predictor of Disordered Eating and Depression in Competitive Endurance Athletes At High Risk of Low Energy Availability (LEA)

Giannopoulou I1, G Wright1, M Kotopoulea-Nikolaidi1, K Martyn1, S Kurucz1, P Watt1

1School of Sport and Health Sciences, University of Brighton, England

Endurance athletes are at high risk for low energy availability (LEA), disordered eating (DE) and related mood disturbances. Mindfulness in eating has been shown to be a predictor of eating psychopathology and depression in healthy and clinical populations; however, there is paucity of research in athletes. The purpose of this study was to compare the levels of mindfulness in eating in competitive endurance athletes at risk of LEA, recreationally active and sedentary individuals, and investigate its predictive power in DE and mood disturbances. A total of 638 participants volunteered to participate in the study. 244 were competitive endurance athletes (EA), 196 recreationally active (RA) and 198 sedentary (SED) (age: 33 ± 0 y old; males:197, females:439; other:2). The Mindful Eating (MEQ), Low Energy Availability in Females (LEAF-Q), Eating Disorder Examination (EDE-Q 6.0) and Profile of Mood State (POMS) questionnaires were used. Results: EA and SED individuals exhibited lower global scores in mindfulness in eating than RA (EA: 3.43; SED: 3.42; RA: 3.53, p< 0.03). Of the 244 EA, 23.5% were at risk of LEA, with females exhibited higher levels of LEA than males (35% Vs. 5%, respectively), while RA individuals exhibited a 17% LEA risk. Athletes at risk of LEA had lower mindfulness in the emotional eating MEQ subscale (p< 0.04), higher depression (p< 0.02), total mood disturbance (TMD) (p< 0.02) and EDE-Q (p< 0.001) scores than athletes with no LEA risk. The mindful eating global score was negatively correlated with TMD (−0.33, p< 0.01), depression (−0.17, p< 0.02) and EDE-Q score (−0.27, p< 0.01) in endurance athletes, and was found to be a predictor of depression and EDE-Q score, explaining respectively, 20% and 30% of their variance. Conclusions: Mindfulness in eating is negatively correlated and can predict the risk of DE and mood disturbances in competitive endurance athletes at risk of LEA. More research is needed to investigate the use of mindful eating as a diagnostic and intervention tool in high-risk LEA athletes and recreationally active individuals.

Plasma Amino Acid Availability Following the Ingestion of a Variety of Non-Animal Derived Proteins in Young and Older Adults

van der Heijden I1, TJA Finnigan2, DR Abdelrahman3, AJ Murton3, FB Stephens1, BT Wall1

1Department of Sport and Health Sciences, College of Life and Environmental Sciences, Heavitree Road, University of Exeter, UK

2Marlow Foods Ltd, Station Road, Stokesly, North Yorkshire, UK

3Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA

The rise in muscle protein synthesis rates following dietary protein ingestion is largely dictated by the systemic rise in (essential) amino acid concentrations, and leucine in particular. However, minimal data exist on the plasma amino acid availability following consumption of non-animal derived protein sources. We assessed the postprandial aminoacidaemic response following the ingestion of isonitrogenous boluses of fungi, algae and plant derived dietary proteins, when compared with an animal-derived control protein. Twelve healthy young (m/f: 6/6, age: 22 ± 1 y, BMI: 22 ± 1 kg·m2) and 10 older (m/f: 5/5, age: 69 ± 2 y, BMI: 24 ± 1 kg·m2) adults participated in a randomised, double-blind, crossover trial. During each visit, volunteers consumed 30 g of protein obtained from milk, mycoprotein, spirulina, chlorella, pea or lupin. Repeated arterialised venous blood samples were collected over a 5-h postprandial period to assess circulating amino acid concentrations (data presented for 7 young and 7 older participants). Protein ingestion increased plasma leucine, essential and total amino acid concentrations in young and older adults (all P< 0.0001), with the highest peak responses following spirulina and pea protein ingestion, and the lowest following chlorella and milk protein ingestion (time × protein; all P< 0.0001). Consequently, total postprandial plasma leucine, essential and total amino acid availability (i.e. postprandial AUC) was different between sources (all P< 0.0001), with greater values observed following mycoprotein, spirulina and pea protein than chlorella, lupin and milk protein ingestion (P< 0.05). Postprandial leucinaemia and aminoacidemia of individual protein sources was not modulated by age (age, protein × age effects; all P> 0.05) but collapsed data across protein sources showed different kinetics between young and older adults (time × age effects; all P< 0.0001). Specifically, postprandial plasma leucine and essential amino acid concentrations increased more rapidly (from 0 to 30 min) in young compared with older adults (P< 0.05). In conclusion, the ingestion of a variety of non-animal derived dietary protein sources elicits divergent plasma amino acid kinetics and overall availability which is further modulated by age.

The Effect of Combined Jump Training and Collagen Supplementation on Bone Mineral Density in Elite Male and Female Cyclists

Hilkens L1,4, N van Schijndel1, VCR Weijer1,4, L Decroix2, J Bons3, LJC van Loon1,4, J-W van Dijk1

1School of Sport and Exercise, HAN University of Applied Sciences, Nijmegen, the Netherlands

2Team Jumbo-Visma (Professional Cycling Team), Den Bosch, the Netherlands

3Central Diagnostic Laboratory, Maastricht University Medical Centre+, Maastricht, the Netherlands

4Department of Human Biology, NUTRIM, Maastricht University Medical Centre+, Maastricht, the Netherlands

Accumulating evidence suggests that most elite cyclists have low bone mineral density (BMD). The present study assessed the effect of combined jump training and collagen supplementation on BMD in elite cyclists. In this open-label, randomized controlled study with two parallel groups, 36 early career elite male (n=8) and female (n=28) cyclists (21 ± 3 y, BMI 21 ± 1 kg/m2) were allocated to either an intervention (INT: n=18) or a no treatment control (CON: n=18) group. The 18-wk intervention period, conducted during the off-season, consisted of 5-min jumping exercise bouts performed five times a week, with each exercise bout preceded by the ingestion of 15 g hydrolysed collagen. Before and after the 18-wk period, body composition, and BMD of the total hip, femoral neck, lumbar spine and whole body were assessed by dual-energy x-ray absorptiometry, along with serum bone turnover markers P1NP and CTX-I. The effect of the intervention on BMD was assessed by using mixed model ANOVA, with time (pre- and post- intervention) as within-subject factor and treatment (CON vs INT) as between-subject factor. Despite a similar increase in lean body mass in CON (Δ1.2 kg, 95%CI: 0.6 to 1.9) and INT (Δ1.1 kg, 95%CI: 0.6 to 1.7; time x treatment, P=0.78), fat mass was unchanged in CON (Δ − 0.1 kg, 95%CI: −0.7 to 0.6), while a decrease was noted in INT (Δ − 1.5 kg, 95%CI: −2.2 to −0.9; time x treatment, P< 0.01). BMD of the femoral neck decreased in CON (Δ-0.015 g/cm2, 95%CI: -0.024 to -0.006), while being preserved in INT (Δ0.006 g/cm2, 95%CI -0.005 to 0.016; time x treatment, P< 0.01). No differences between groups were observed for changes in BMD at the total hip, lumbar spine and whole body (time x treatment, P> 0.05 for all). Serum P1NP concentrations decreased to a similar extent in CON (Δ-12 ng/mL, 95%CI: -22 to -3) and INT ((Δ-17 ng/mL, 95%CI: -24 to -9; time-effect, P< 0.001; time x treatment, P=0.22). Serum CTX-I concentrations were relatively stable over time, with no differences between groups (time-effect, P=0.08; time x treatment, P=0.58). In conclusion, frequent short bouts of jumping exercise combined with collagen supplementation beneficially affect femoral neck BMD in elite cyclists. Hence, this intervention appears a promising strategy to counteract the negative impact of professional cycling on bone health.

The Effect of Low Dose Sodium Bicarbonate Consumption on Consecutive Days on High-Intensive Long-Term Exercise Performance

Aktitiz S1, ŞN Koşar1, HH Turnagöl1

1Division of Exercise Nutrition and Metabolism, Faculty of Sport Sciences, Hacettepe University, Turkey

Sodium bicarbonate (SB) is the primary ergogenic nutritional supplement that improves the extracellular buffering system by removing H+ ions from the blood. In addition to anaerobic exercises, there is evidence that SB can be an effective ergogenic aid for continuous aerobic exercises performed at anaerobic threshold (AT). However, because the most common dose of SB (0.3 g/kg) causes gastrointestinal symptoms (GIS), alternative supplementation protocols are necessary. This study aims to compare the effects of acute and consecutive days of low-dose SB consumption on high-intensity endurance exercise performance. After determining the AT, 12 recreational male cyclists (Age: 31 ± 5y; Training years: 6 ± 4y; VO2peak: 48 ± 8ml/kg/min) participated in performance tests three times in random order following acute SB intake (ASB), SB consumption on consecutive days (CSB), and placebo intake on consecutive days (PLA). Participants were given a placebo for 4 days and then 0.2 g/kg SB on the morning of the test for ASB; 0.2 g/kg/day SB for 4 days and a placebo on the morning of the test for CSB; and a placebo (table salt) for 4 days as well as on the morning of the test for PLA. They performed an endurance test on a bicycle ergometer at 95% of the AT for 30 minutes, followed by a time to exhaustion test at 110% of the AT, 90 minutes after the last supplement. Blood lactate, pH, and bicarbonate levels were measured at rest, after 30 minutes of exercise, and at the time of exhaustion. Two-way repeated measures of ANOVA was used for data analysis. Blood bicarbonate levels at rest were higher in CSB (25.8 ± 1.6 mmol/L) and ASB (27.5 ± 1.5 mmol/L) than PLA (23.8 ± 1.4 mmol/L) (p< 0.001). CSB increased the time to exhaustion (54.3 ± 9.2 min) than PLA (49.8 ± 10.8 min) (p< 0.05). Time to exhaustion following ASB (51.2 ± 8.4 min) was comparable to that of CSB and PLA (p> 0.05). Blood pH, bicarbonate, and pCO2 in ASB and CSB were higher at rest, at the 30th minute of exercise, and at the time of exhaustion than PLA (p< 0.05). While no GIS was observed in CSB, 30% of the participants experienced diarrhoea and bloating prior to the performance test in ASB. In conclusion, low-dose bicarbonate intake on consecutive days improved the time to exhaustion during prolonged high-intensity exercise relative to placebo and prevented gastrointestinal side effects.

The Ergogenicity of Acute Histidine-Containing Dipeptide Ingestion: Is Balenine a Better Alternative to Carnosine and Anserine Supplementation?

Lievens E1, S de Jager Sarah1, W Derave Wim1

1Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium

Carnosine and its methylated variants, anserine and balenine, are histidine-containing dipeptides known for their various health and performance promoting properties. Acute combined carnosine and anserine supplementation was shown to ameliorate short, maximal performances. Up to now, the underlying mechanism remains elusive, yet the effects appear to be related to the dipeptides’ plasma bioavailability. Since in vitro studies show a superior plasma stability of balenine in comparison to its variants, this might be an even better nutritional aid. As balenine has never been administered to humans, a pharmacokinetic study was conducted, followed by a crossover performance study in which the acute ergogenic effect of balenine was investigated. In the pharmacokinetic study, six volunteers acutely ingested three increasing doses (1, 4 and 10 mg/kg bodyweight) after which plasma was collected several times for 24 hours. Repeated measures ANOVA showed that peak concentration increased (p=0.0005) exponentially with the three increasing doses. Ten mg/kg elicited a concentration of 28.2 ± 7.4 μM, without evoking side-effects. Since this peak concentration was higher than what is achieved with 30 mg/kg of carnosine and anserine, 10 mg/kg of balenine was applied in a performance study. Twenty recreational cyclists conducted three maximal voluntary contractions (MVC), three 6 s cycling sprints, a 4 and 20 km time trial (TT) following acute ingestion of either a placebo or balenine. Paired samples t-tests revealed no differences between both conditions on MVC (p=0.3169; 95%CI = -3.868 to 1.320), cycling sprints (p = 0.3553; 95%CI = -3.119 to 8.279), 4 km TT (p=0.8566; 95%CI = -2.670 to 2.240), nor the 20 km TT (p=0.2660; 95%CI = -0.1256 to 0.4296). Overall, acute balenine ingestion was unable to improve the types of performances previously shown augmented by carnosine and anserine. This may indicate that balenine’s functional characteristics do not entirely resemble those of carnosine and anserine.

A Cross Sectional Study to Access Special Judo Physical Fitness and Nutritional Profile in Judo players of Belgavi District, India

Kour H,1 N Ashwini2

1Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India

2Dept. of Clinical Nutrition and Dietetics, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India

Judo, as a sport is not well known in India. Nutrition is an important part of training regimens and performance of an athlete. The strength and physical fitness of a sports person mostly depends on the intake of appropriate nutrition through training period and off season. This study was conducted to assess the Nutritional Profile, Physical Fitness and anthropometric parameters of Judo Players of Belagavi District. This cross sectional study was conducted on 24 judo players of 18-25 y who were practicing regularly for a minimum period of 3 years. Information about their practice schedule, number of players and their availability was collected from the Judo coaches. Descriptive data of the participant’s age, medical history, training schedule regarding number of years of judo practice, number of days in a week, number of hours per day, dietary history were obtained by interviewing the participants. Players were divided into A and B group depending on > or ≤ 5 years of judo training. Anthropometric parameters were measured, skin fold thickness was noted at seven sites, body fat % was calculated using Siri’s Equation, and Physical fitness was evaluated by Harvard Step Test and Special Judo fitness test. Flexibility was tested using Sit and Reach flexibility, Agility was assessed by side step test. Nutritional status was obtained by using pre designed questionnaire and 24 hour dietary recall method. Players were briefed about the nature of the study and written informed consent was obtained. Difference between the mean of the two groups was tested using Students unpaired ‘t’ test, where significance of the p value was < 0.05. Anthropometric findings of both the judo groups were the same. The average energy intake was 2246 Kcal, 94 g protein, 309 g carbohydrate and 76 g of fat. Body fat has negative correlation (r =-0.690, P< 0.05) with performance in SJFT. Mean Flexibility score was higher for Judo B group than Judo A group. The data provides the judo player with information on ideal profile and where training might be directed to compensate for areas where the athlete is below average for successful judo players.

Assessment of Dietary Fat Intake Amongst Division III Collegiate Athletes

Sterringer T1,2, DE Larson-Meyer1, L Cialdella-Kam2,3

1Dept of Human Nutrition, Foods, and Exercise, Virginia Tech, United States

2Dept of Nutrition, School of Medicine, Case Western Reserve University, United States

3Warfighter Performance Department, Naval Health Research Center, United States

The type of dietary fat consumed may affect athletic performance and recovery. Excess saturated fat is associated with increased inflammation and oxidative stress whereas omega-3 fatty acids may attenuate inflammation and reduce the oxygen cost of exercise, thereby supporting sports performance. This retrospective chart review assessed the dietary fat intake of United States (US) National Collegiate Athletic Association athletes (n=56; 16 men, 40 women) competing at the Division III level in five sports (wrestling, tennis, track, basketball, swimming). Dietary intake was assessed from 3-day food intake records using nutrient analysis software (ESHA Research Food Processor). The American College of Sports Medicine (ACSM) sports nutrition guidelines, US Dietary Guidelines for Americans, and United Kingdom (UK) health guidelines were used as comparison standards for total and saturated fat intake (absolute and percent of total energy intake, % kcal). One-sample t-tests were used to compare reported intake to recommended guidelines and reported as mean±SD. Total fat (% kcal) was 33 ± 6% and within the ACSM guideline of 20-35%. Saturated fat was 10.7 ± 3.0% of total kcal and similar to the US guidelines of < 10% kcal; however, 32 athletes had intakes > 10%. Absolute saturated fat intakes (g/day) were 32 ± 13 and 27 ± 78 for male and female athletes, respectively. Intake for the men was in line with the UK health guidelines. Female athletes, however, exceeded the UK recommendation for women of no more than 20g/day of saturated fat (p< 0.001). Omega-3 fatty acid intake was 0.4 ± 0.5g/day, which is lower than the recommended target range of 2-4g/day for athletes (p< 0.001). Omega-6 fatty acid intake was 3.1 ± 2.3g/day, and the omega-6/omega-3 ratio was 10.5 ± 6.9. Based on these findings, athletes could improve the quality of their fat intake by incorporating more dietary sources of omega-3 fatty acids while reducing foods high in saturated fat.

Energy Expenditure and Physical Load in Professional Female Football Players in the Dutch Female League: Implications for Nutritional Counselling

Brinkmans N1,2, G Plasqui2, LJC van Loon2, JW van Dijk1

1Institute of Sports and Exercise Studies, HAN University of Applied Sciences, Nijmegen, The Netherlands

2NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands

While substantial information is available on the nutritional requirements of male football players, the nutritional requirements of female football players have yet to be established. The aim of this study was to assess total daily energy expenditure in professional female football players, along with measurements of body composition and physical load. Fifteen professional football players (age: 23 ± 5 y; body mass (BM): 61.7 ± 3.3 kg; body fat%: 19.1 ± 3.0 %; fat-free mass (FFM): 49.9 ± 3.6 kg) playing in the highest Dutch Female League (Female Eredivisie) were included in this observational study. During a 14-day period in the competitive season total energy expenditure (TEE) was assessed by the doubly labelled water method. Resting metabolic rate (RMR) was measured by ventilated hood indirect calorimetry and body composition by dual X-ray absorptiometry. Physical Activity Energy Expenditure (PAEE) was calculated from TEE, RMR and estimated dietary induced thermogenesis (DIT; 10% of TEE): PAEE = TEE – (RMR + DIT). Training and match load (time, distance and high intensity running distance (≥ 19km/h)) were measured using local position measurement technology. Over the 14-day period, players spent 569 ± 77 minutes on the field and covered 39.1 ± 8.3 km, of which 1.3 ± 0.5 km on high intensity. TEE was 2882 ± 278 kcal/day (58.1 ± 4.6 kcal/kg FFM), with a RMR of 1413 ± 129 kcal/d and a PAEE of 1200 ± 219 kcal/d. TEE correlated well with FFM (r=0.63, p=0.012), but not with BM (r=0.21, p=0.45). When expressed relative to FFM, both TEE and PAEE correlated strongly with total time on the field (r=0.71, p=0.009 and r=0.75, p=0.007, respectively) and distance covered (r=0.65, p=0.021 and r=0.66, p=0.026, respectively). Relative to fat-free mass, the energy requirements of professional female football players are considerably higher than previously reported in professional male football players. The high daily energy requirements can be explained by the substantial PAEE, which is strongly related to the physical load. Sports nutritionists and future nutritional guidelines should consider the differences in energy requirements between female and male football players.

Do Paralympic Athletes Suffer From Brittle Bones? The Prevalence of Low Bone Mineral Density in a Representative Cohort of Paralympic Athletes

Weijer VCR1,2; KL Jonvik3; L Risvang3, LJC van Loon2; T Raastad3; JW van Dijk1

1School of Sport and Exercise, HAN University of Applied Sciences, Nijmegen, the Netherlands

2NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands

3Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway

The growing interest in Paralympic sports is accompanied by an increased attention for the health of Paralympic athletes. Bone health may be a concern, given the blunted osteogenic stimuli in wheelchair and prostheses users, along with potential nutritional deficiencies. The aim of this study was to explore the bone mineral density (BMD) of Paralympic athletes from various sport disciplines. A total of 64 Paralympic athletes (para cycling (n=16), wheelchair tennis (n=9) wheelchair basketball (n=18), para cross-country skiing (n=6) and various other sports (n=15)), 48% of whom were wheelchair-dependent, were included in this cross-sectional study. Dual-energy x-ray absorptiometry scans of the whole-body, lumbar spine, total hip, and femoral neck were analyzed for BMD Z-scores. Data are reported as mean±SD. Comparisons between groups were conducted by one-way ANOVA with Bonferroni correction. For whole-body BMD, 20% of all athletes had a Z-score below -1.0, which is the clinical cut-off level of low BMD. When assessed at the lumbar spine, total hip, and femoral neck, the prevalence of low BMD was 19, 34 and 40%, respectively. At the lumbar spine, wheelchair basketball players had a higher BMD Z-score (0.9 ± 0.7) than to para cyclists (-0.4 ± 0.9; P=0.001), cross-country skiers (-0.5 ± 1.3; P=0.037), and other athletes (-0.4 ± 0.8; P=0.005). Furthermore, wheelchair tennis players tended to have a higher lumbar spine BMD Z-score (0.7 ± 0.6) than para-cyclists (P=0.053). The total hip and femoral neck BMD Z-scores of wheelchair-dependent athletes (-1.3 ± 1.1 and -1.1 ± 1.2, respectively) were lower than non-wheelchair-dependent athletes (-0.1 ± 1.1 and -0.1 ± 1.1, respectively). For the whole-body and lumbar spine there were no differences between wheelchair- and non-wheelchair-dependent athletes. In conclusion, low BMD in Paralympic athletes is mainly prevalent in the hip region. More specifically, the hip region seems to be mainly affected in wheelchair-dependent athletes. The BMD of the lumbar spine does not seem to be compromised in wheelchair basketball and tennis players, suggesting ample osteogenic stimuli for the lumbar spine in those particular wheelchair sports.

Characterization of the Lipid Profile of Mature Erythrocyte Membranes in Elite Female Football Players

Peña N1, J Amézaga1, G Marrugat1, A Cano1, J Arce2, J Larruskain2, A Landaluce2, T Viar2, J Lekue2, I Tueros1

1AZTI, Food Research, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain

2Medical Services, Athletic Club, Lezama, Spain

An optimal and correctly balanced metabolic status is essential to improve sports performance in athletes. Nutritional status in athletes is typically evaluated through anthropometric measurements, nutritional interviews, and blood tests. Recent advances in omic tools, such as the lipid profile of the mature erythrocyte membranes (LPMEM), allow to better characterize the metabolic status of these individuals and to provide personalised recommendations about their need for nutrients, such as omega-3, omega-6, and others. This work aimed to study the LPMEM in professional women football players during the football season and compare it with those defined as optimal values to define personalized nutritional strategies. An observational study was carried out on female football players from the Athletic Club (Bilbao) playing in the first division of the Spanish league. Blood samples were collected at three points: at the beginning, mid-season, and end of the season for three consecutive seasons (2019-2020, 2020-2021, and 2021-2022), providing a total of 160 samples from 40 women. LPMEM was measured by GC-FID after previous selection of the mature erythrocytes. The results of the quantification of fatty acids (FA) from the athletes showed some variations when comparing with the optimal values. We observed that the 70% of the female football players had lower values for omega-6 dihomo-γ-linolenic acid (DGLA); however, the 89%, 44% and 81% of the participants showed higher values for omega-6 arachidonic acid (AA), omega-3 eicosapentaenoic acid (EPA) and the ratio of saturated and monounsaturated fatty acids (SFA/MUFA) when comparing with optimal values. Regarding the evolution through sampling points, we showed increase in omega-6 AA (p = 0.007) and total polyunsaturated fatty acids (PUFA) (p < 0.0001) over football season. In conclusion, there were relevant variations in several fatty acids of the lipid profile of elite female footballers throughout the season and compared to the general population. This fact should be considered when defining a personalized nutritional strategy (diet and supplementation) for female football players.

Effect of Short-Term Low Energy Availability on Body Mass and Physiological, Endocrine, and Metabolic Responses in Males

Taylor HL1, WL Foo1, S Shepherd1, J Burniston1, C Langan-Evans1, J Morton1, J Areta1

1Liverpool John Moores University

Physiological responses to 'low’ energy availability (LEA) in controlled conditions are well characterised in females but remain largely uncharacterised in males. This study aimed to assess the effect of short-term LEA on body mass, endocrine, metabolic, and physiological responses in males. Ten healthy, active, males (age: 25 ± 5 y, body mass: 78.8 ± 8.2 kg, VO2peak: 51.7 ± 7.7 ml/kg/min) completed 10 consecutive days of dietary and exercise control comprising 5 days of energy balance (EB) followed by 5 days of LEA. Each 5-day period included 3 days of cycloergometry to expend 15 kcal/kg Fat Free Mass (FFM)/day. During EB and LEA, the provided energy intake elicited energy availabilities of 45 and 10 kcal/kg FFM/day, respectively. Energy intake was 60% carbohydrate, 20% fat and 20% protein. Body composition and resting metabolic rate (RMR) were measured at the start and end of each period and fasted venous blood samples were collected throughout. Data were examined via one-way ANOVA and linear mixed models. Body mass, FFM and fat mass remained stable during EB and were reduced by 2.9 ± 0.7 kg (P < .001), 2.1 ± 0.7 kg (P < .001), and 0.8 ± 0.6 kg (P = .003) respectively after LEA. RMR was stable throughout (P = .151), but respiratory exchange ratio reduced from 0.87 ± .08 to 0.77 ± .05 (P = .003) following LEA. Compared to baseline total tri-iodothyronine (T3) concentrations (131 ± 22 ng/dL), plasma T3 was reduced after two days (103 ± 25 ng/dL; P = .001), four days (100 ± 26 ng/dL; P < .001), and five days (108 ± 23 ng/dL; P = .009) of LEA. Plasma testosterone (T) concentrations were stable during EB, but reduced from 5.94 ± 1.76 to 5.09 ± 0.96 ng/ml (P = .023) after five days of LEA. Plasma ß-CTX was higher on day five of LEA (0.90 ± 0.23 ug/L) than on day five of EB (0.80 ± 0.29 ug/L; P = .020). P1NP concentrations were stable throughout EB but reduced from 79.3 ± 22.7 μg/L to 67.3 ± 17.8 μg/L (P < .001) across LEA. Plasma glucose was stable throughout the study (P = .313). Non-esterified fatty acid concentrations increased across LEA from 0.47 ± 0.36 mmol/L to 0.88 ± 0.39 mmol/L (P < .001). Short-term LEA in males elicited a marked decrease in body mass, while modulating concentrations of T3, T, and markers of bone resorption and formation, but had no effect on resting metabolic rate. Responses to LEA in males follow a similar pattern to what has been reported in females.

Acute Ketone Monoester Supplementation Impairs 20-Minute Time-Trial Performance in Trained Cyclists: A Randomized, Double-Blind, Crossover Trial

McCarthy DG1, J Bone1, M Fong1, W Bostad1, PJM Pinckaers2, DL Richards3, LJC van Loon2, and MJ Gibala1

1Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada

2Department of Human Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands

3Department of Medicine, McMaster University, Hamilton, Ontario, Canada

Acute ketone monoester (KE) supplementation induces hyperketonemia as commonly reflected by an increase in the ketone body β-hydroxybutyrate (β-HB) in venous blood. This practice can alter exercise responses but the effect on performance is unclear. The limited and equivocal data to date are likely related to factors including the KE dose, test conditions, and caliber of athlete studied. Acute KE ingestion that increases [β-HB] to ∼1-3 mM has been purported to be ergogenic for endurance-type performance. We tested the hypothesis that mean power output during a 20-min cycling time-trial (TT) would be different after KE ingestion compared to a ketone-free placebo (PL). This performance test is strongly correlated with functional threshold power (i.e., highest sustainable power over 1-h) and the day-to-day coefficient of variation using the same equipment and procedures as the present study was ∼1.4% (doi:10.1123/ijspp.2018-0100). An a priori sample size calculation (G*Power v3.1) estimated that n=22 provided 80% power to detect an effect size dz of 0.63 at an alpha level of 0.05 with a 2-tailed paired t-test. This determination considered 2.0% as the smallest meaningful difference in performance. N=23 trained cyclists (21 males, 2 females; peak oxygen uptake: 65 ± 12 mL/kg/min; mean±SD), who were regularly cycling > 5 h/week, completed a familiarization trial followed by two experimental trials. Participants self-selected and replicated their diet and exercise for ∼24 h before each trial. Participants ingested either 0.35 g/kg body mass (27 ± 4 g) of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate KE or a flavour-matched PL 30 min before exercise in a randomized, double-blind, crossover manner. Exercise involved a 15-min warm-up at a self-selected pace followed by the 20-min TT on a cycle ergometer (Velotron). The only feedback provided was time elapsed. Pre-exercise venous [β-HB] was higher after KE vs PL (2.0 ± 0.6 vs 0.2 ± 0.1 mM, p< 0.0001). Mean TT power output was 2.4 [0.6 to 4.1]% (mean[95% CI]) lower after KE vs PL (255 ± 54 vs 261 ± 54 W, p< 0.01; dz=0.60). [β-HB] was not correlated with the change in mean TT power output (p=0.85). The mechanistic basis for the impaired 20-min time trial performance after KE ingestion in trained cyclists remains to be determined. (NCT05226962)

Assessment of Disordered Eating Habits and Behaviours Amongst Personal Trainers Using the Eating Disorder Examination-Questionnaire (EDE-Q): A Pilot Study

Carroll M1, K Cradock1

1Department of Health & Nutritional Sciences, Atlantic Technological University, Ireland

Disordered eating (DE) is a global phenomenon and has huge potential to adversely impact the mental and physical health of individuals and if left untreated, may progress to a clinical eating disorder. The causes of DE are multifactorial. Personal trainers are exposed to many of these risk factors over the course of their working life. The fitness industry itself is largely appearance-based, with individuals feeling the need to maintain a certain physique to achieve success in their careers. Many personal trainers also use their physique to garner business, a phenomenon known as physical capital. This study aimed to investigate the prevalence of DE behaviours amongst UK/Ireland-based personal trainers. Personal trainers were recruited via social media posts on Twitter and Instagram. Overall EDE-Q score, subscale scores and prevalence of clinically significant EDE-Q scores were assessed. Further questions identified the frequency and severity of disordered behaviours amongst personal trainers. 78 personal trainers answered an online version of the EDE-Q. Personal trainers exhibited a mean EDE-Q score of 1.30, which is higher than previous research on other health/fitness professionals. 15% of the population surveyed had a clinically significant EDE-Q score, which places them at increased risk of developing an eating disorder. In addition, results highlighted high levels of engagement in DE behaviours such as binge-eating, dietary restriction and over-exercising. This study highlights a need to further investigate the relationship between personal trainers and DE, in addition to investigating the prevalence of and severity of DE in other fitness professionals.

Dietary Habits and Physical Activity Associate With Visceral Fat During Menopause

Hietavala EM1, T Törmäkangas1, EK Laakkonen1

1Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland

Menopausal loss of ovarian function and subsequent ceasing of cyclic estradiol secretion is considered as the trigger for accumulating adiposity. Overall weight gain may be due to aging, whereas increased amount of visceral fat (VF), a correlate of cardiometabolic disease risk, is suggested to be due to menopause. We investigated whether eating behaviour and food intake associate with VF in pre-, peri- and postmenopausal Finnish women. The cross-sectional data was collected from the 47–55-year-old women participating in the ERMA study (n=1098). Their menopausal status (pre-, early peri-, late peri- and postmenopausal; PREM, EPM, LPM and POSTM, respectively) was defined using menstrual diaries and hormone measurements following the STRAW+ 10-guidelines. Participants’ current dietary habits were examined with a questionnaire; eating behaviour was examined with 13 questions and food intake with a 45-item food frequency questionnaire. The amount of VF was assessed by bioelectrical impedance analysis (InBody 720). Eating behaviour and food intake were tested separately for association with VF using linear regression analysis in four menopause groups. Models were adjusted for self-reported physical activity, body height, and educational level. In menopausal groups (PREM, EPM, LPM and POSTM), eating behaviour model explained 28, 21, 25 and 24% of VF variance, respectively (all: P≤ 0.001). R2 for eating behaviour was 18 (P< 0.001), 11 (P=0.063), 13 (P=0.007) and 12% (P< 0.001) in the menopause groups, respectively. Food intake model explained 32 (P=0.008), 36 (P=0.489), 37 (P=0.022) and 30% (P=0.001) of VF variation in the menopause groups, respectively. R2 for food intake was not statistically significant in any group. Physical activity was associated with VF in both regression models and in all menopause groups (all: P≤ 0.002). Especially more frequent snacking and evening-oriented eating, and stronger desire to restrict one’s food intake associated with higher amount of VF. Our results suggest that to hamper the increase of VF and hence to support the health of menopausal women, it is important to pay attention to eating behaviour, not only foodstuffs consumed. In addition, it is important to stay physically active throughout the menopausal transition.

Hormonal Contraceptive Use and Endogenous Hormones in Female Finnish Fitness Athletes After a Period of Decreased Energy Availability

Mikkonen R1, J Hulmi1, V Isola1, V Salmi1, I Löfberg1, J Ahtiainen1, J Ihalainen1

1Faculty of Sport and Health Sciences, University of Jyväskylä, Finland

Decreased energy availability (EA) can alter endogenous hormonal milieu, but the influence of hormonal contraceptives on these changes has yet to be elucidated. The purpose of this study was to examine the influence of hormonal contraceptive use on endogenous hormones after a period of reduced EA. Thirty-two women (age: 27 ± 4 y (mean±SD); height 166 ± 5 cm; body mass 66 ± 7 kg) who participated in a Fitness Sports (body building) study were included in three self-identified groups: combined hormonal contraceptive users (CHC, n=10), progestin only users (PHC, n=9), and no current hormonal contraceptive use (NHC, n=13). Length of diet was 22 ± 4 wks where EA decreased from 40 ± 9 to 26 ± 7 kcal/kg fat free mass/day. Energy availability (EA) was calculated from energy intake and exercise energy expenditure as well as fat free mass. Serum hormones were analysed from fasting venous blood samples. Menstrual/hormonal contraceptive cycle phase was not controlled for. Body mass, fat mass, fat-free mass, body fat percentage, and EA decreased (p< 0.001) whereas a decrease in estradiol was observed (p=0.042) in all groups from pre to post. CHC had higher serum cortisol than both PHC and NHC (p=0.012 and p< 0.001, respectively). A time x group interaction was observed in serum IGF-1 where a decrease was observed in all groups p=0.007–p< 0.001 and IGF-1 in CHC was lower than PHC at pre (p=0.019) and NHC at pre and post (p< 0.001 and p=0.022). A time x group interaction was also observed in total testosterone where a decrease was observed in PHC (p=0.004) and NHC (p< 0.001) but not in CHC. At post, total testosterone was higher in CHC than PHC and NHC (p≤ 0.001). While no differences between groups in absolute decreases in body mass, fat mass, fat-free mass, body fat percentage, EA and estradiol were observed, our results suggest that combined hormonal contraceptives might influence hormonal milieu differently than progestin only or no hormonal contraceptive use during a period of reduced EA.

Prevalence of Markers of Relative Energy Deficiency in Male Leanness Athletes and Their Controls

Ihalainen JK1, M Valtonen2, RS Mikkonen1, K Mjøsund3

1Faculty of Sport and Health Sciences University of Jyväskylä, Finland

2Finnish Institute of High Performance Sport KIHU, Jyväskylä, Finland

3Paavo Nurmi Centre, Sport and Exercise Medicine Unit, University of Turku, Turku, Finland

Body mass influences performance in many sports, including endurance and jumping events. However, an effort to target a specific physique for performance should not compromise health. Challenges related to Relative Energy Deficiency in Sports (RED-S) such as unfavorable metabolic adaptations and low bone mineral density (BMD) have been reported in male athletes. This study aimed to determine the prevalence of biomarkers for RED-S in male athletes competing in lean sports and in their controls. A total of 50 national or international level trained male athletes (age=24 ± 4 y, height 1.81 ± 0.07 m, body mass 71.5 ± 9.5 kg [mean±SD]) and 18 physically active controls (age=24 ± 1 y, height 1.83 ± 0.05 m, body mass 86.3 ± 11.4 kg) were recruited for the study. Laboratory assessments for resting metabolic rate (RMR), body fat percentage, bone mineral density (BMD, Z-score), blood hormonal biomarkers (free triiodothyronine [fT3], cortisol, testosterone, low-density lipoprotein) were conducted on all participants. RED-S criteria were defined similar to Stenqvist et al. (2021). Athletes had lower BMI (21.7 ± 2.0 vs. 25.7 ± 3.2 kg·m-2; p< 0.01), body fat percentage (7.3 ± 2.4 vs. 16.9 ± 6.1%; p< 0.001), fT3 (4.6 ± 1.1 vs. 6.1 ± 1.7 pmol·L-1; p< 0.001), and lumbar Z-score (0.3 ± 1.0 vs. 1.4± 0.2; p< 0.001) than the controls. Of the 50 athletes 24 (48%) had 0 or 1 RED-S criteria present, 16 (32%) athletes had two criteria, 4 athletes (8%) had three criteria, four athletes (8%) had four criteria, one athlete (2%) had five and one athlete (2%) had six criteria. In the control group 13 participants (72%) had 0 or 1 RED-S criteria and five participants (27%) had had two RED-S criteria. There was a difference between the groups in the prevalence of RED-S criteria (Chi-square test=5.410, p=0.028). In line with previous studies, the prevalence of the RED-S criteria in the present study involving high-level lean athletes was high. Approximately half of the leanness athletes had none or one RED-S criteria, whereas we were able to identify an athlete having six out of eight RED-S criteria. Stenqvist TB et al. (2021). Int J Sport Nutr Exerc Metab, 31(6), 497-506.

Ketone Monoester Supplementation Does Not Affect Multimodal Endurance Exercise Performance Regardless of Blood Ketone Levels

Isherwood A1,2, A Wythe1, L Hodson2, K Clarke1, D Dearlove1,2

1The Department of Physiology, Anatomy, and Genetics (DPAG), The University of Oxford, Oxford, England

2The Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), The University of Oxford, Oxford, England

Exogenous ketosis achieved through ingestion of the ketone monoester (KME) alters metabolic responses to exercise, but ergogenic effects on performance are equivocal. It may be that blood ketone levels must be elevated to a sufficient extent above physiological levels to achieve an ergogenic effect. Here we explored the interaction effect between KME dosage and du-/triathlon (bike-to-run) performance, in a post-prandial state. In a 3-arm, double-blind, counterbalanced-randomised crossover study, 8 well-trained du-/triathletes (6M/2F) performed 1 h of steady-state ergometer cycling exercise at 70 % V˙O2peak power before immediately undertaking a self-paced 10 km running time trial (TT) on a powered treadmill. Two hours prior, participants consumed a ‘gold standard’ (2 g/kg BW) high carbohydrate (CHO) breakfast and were provided with CHO drinks (75 g/h). Additionally, athletes consumed either 860 mg·kg-1 KME (High-KME), 573 mg·kg-1 KME (Low-KME), or placebo (PLA). V˙O2, heart rate (HR), RPE, appetite, and gastrointestinal (GI) distress were monitored, with venous blood samples collected. Plasma [βHB] was elevated in a dose-dependent manner (p < 0.001), being elevated in High-KME (2.45 mM ± 0.53 mM; Mean±SD) vs Low-KME (1.14 mM ± 0.43 mM) (p < 0.001) and Low-KME vs PLA (0.09 mM ± 0.14 mM) (p = 0.004). There was a main effect for condition on plasma [lactate], with levels being supressed with increasing KME dose (High-KME: 2.71 ± 1.64, Low-KME: 3.34 ± 2.31, PLA: 3.74 ± 2.84 mM). Lactate was lower in High-KME vs PLA and Low-KME vs PLA (p < 0.05) during the run, but not the cycle. Blood [NEFA] and [glucose] were not different at any time point between conditions. Performance in the 10 km TT was not different between conditions (High-KME: 2438 ± 212, Low-KME: 2434 ± 218, PLA: 2419 ± 217 sec; p = 0.141). There were no effects of condition for V˙O2, HR, appetite, or Borg RPE (all p ≥ 0.404). Total GI distress did not differ between conditions (p = 0.406), though heartburn, intestinal cramps, and bloating scores were higher in High-KME, and muscle cramp higher in PLA, than the other conditions (p < 0.05). In this study, we demonstrate that supplementing gold standard CHO feeding with a KME drink does not affect du-/triathlon exercise performance, regardless of the dose given and subsequent blood ketone concentrations achieved.

Increased Physical Loading On and Off the Pitch: Demands of Full-Time Academy Programmes and Implications for Growth, Maturation and Bone Health

Stables R1, M Hannon1, N Costello2, L Boddy1, G Close1, J Morton1

1Liverpool John Moores University

2Leeds Beckett University

Physical loading (training, matches, and physical activity) has implications for growth, maturation, and bone health of academy male soccer players. Academy players display training loads comparable to and in some cases, greater than their first team counterparts. However, physical activity of players outside of training and matches remains to be determined. Moreover, it is not yet known if being enrolled in an academy programme increases the physical loading of players. Therefore, the aim of this study was to 1) establish the physical loading of academy male soccer players, and 2) quantify differences in physical loading, energy expenditure (via doubly labelled water) and energy intake of academy players to those from an age matched control group. The physical activity of youth male soccer players from an EPL academy (n=8) and control (n=8) group was quantified using accelerometery over a 14-day assessment period. Training (sessions: academy n=8, control n=2) and match (academy n=2, control n=2) load was quantified using GPS technology. Each day academy players spent more time being physically active (> 200mg; AC:114 ± 26min, CON:78 ± 35min, 95%CI 14 to 54, p< 0.05) than the control group. Academy players spent more time completing moderate (300-450mg; AC:20 ± 5 min, CON:16 ± 6min, 95%CI 0 to 8, p< 0.05) and high (> 600mg; AC:13 ± 4min, CON:7 ± 4min, 95%CI 4 to 9, p< 0.001) intensity physical activity than the academy group. Academy players spent less time completing low (0-150mg; AC:1311 ± 27min, CON:1334 ± 38min, 95%CI -47 to 1, p< 0.05) intensity activity than the control group. Academy players spent a greater duration of time training and competing (AC:978 ± 25 min, CON:396 ± 3 min, 95%CI 563 to 601, p< 0.001) than the control group, which correlated in a greater total distance (AC:54.8 ± 6.9km, CON:21.1 ± 4.0 km, 95%CI 27.5 to 39.8, p< 0.001). We conclude that physical activity, training, and match load are greater in academy soccer players than in age-matched control soccer players who are not enrolled on an academy programme. Although energy intake and energy expenditure data are still being assessed (and will be presented at the conference), the above data suggest that sufficient energy and carbohydrate availability is of paramount importance for academy players to support the energetic cost of training and match schedules.

Effects of a Bone-Specific Resistance Exercise Intervention and Nutrition Optimisation on Bone Mineral Density and Physical Health in Wheelchair-Dependent Para Athletes and Non-Athletes (BoneWheel)

Risvang LC1, V Strøm1,2, T Raastad1, KL Jonvik1,3

1Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway

2Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway

3Sunn Idrett, Norwegian Olympic and Paralympic Committee and Confederation of Sports

Wheelchair (WC) users are at increased risk of low bone mineral density (BMD) due to minimal mechanical stimuli on the skeleton, normally sustained by walking and high impact physical activity achieved by non-disabled. Every 4th person with a spinal cord injury (SCI) will experience one or several fractures during their lives, because of osteoporosis, whereof 70% are low-impact injuries. For WC Para athletes, fractures will disturb training continuity, attenuate performance, and add risk of detriment to their overall physical and mental health. In our ongoing study (ParaNut), WC Para athletes had in general lower BMD in the lumbar spine and hip than their walking counterparts, but with large variation across sports, indicating that the training is not able to attenuate bone loss in most sitting sports. To maintain and improve BMD, physical health and performance, bone-loading exercise is key. Further, optimal vitamin D, calcium and energy availability status is important for bone remodelling. Therefore, the aim of this multi-centre randomized controlled trial is to intervene early in WC-dependent athletic and non-athletic population with low BMD (Z-score < 0). The 24-week intervention will consist of a novel bone-specific resistance exercise programme and nutrition optimisation, where the effect on lumbar spine, hip and femoral neck BMD will be measured. Secondarily, the effects of the intervention on muscular strength, rate of force development, body composition and physical function will be examined. Our hypothesis is that the exercise intervention will increase the lumbar spine BMD with ∼3% as seen in non-disabled over 12 weeks, with an expected larger impact in the non-athletic cohort. We also expect an increase in muscular strength, rate of force development and physical function. Body composition is expected to change minimally, mostly with positive changes in lean mass. The study is a collaboration between Norwegian School of Sport Sciences, Sunnaas Rehabilitation Hospital, Norwegian Confederation of Sports, Norwegian University of Science and Technology, Bergen commune and Sports Cluster West, and the Norwegian SCI Association. The study results will inform practitioners and clinicians working with WC-users, facilitating evidence-based exercise interventions and treatment

Case Study: Nutrition Periodization in an Indian Male National Record Holder Sprint Athlete

Khopkar M1

1Dept. of Rehabilitation and Sports Medicine, Sir H.N. Reliance Foundation Hospital, Mumbai, India

A framework for nutrition periodization in athletics was established as a part of the 2019 IAAF, now World Athletics’ Nutrition Consensus. Very few published case-study examples for periodized nutrition in athletics exist & almost none in an Indian setting. Therefore, the aim of this case-study was to introduce a real-world scenario of an elite male sprinter so that practitioners in the field could implement such practical interventions. This case study features an Indian Male National Record Holder Sprinter implementing periodized nutrition strategies across 4 different training phases (General, Specific, Competition preparation & Main competition) in a double [8 mo. Nov 21-June 22, 3 mo. July 22-Sep 22] periodized year. Macro-cycle [months], meso-cycle [weeks], micro-cycle [days & within-day] based nutrition strategies included modifications in diet [carbohydrate & protein] & supplements [creatine, iron, vitamin D]. Weight (kg) (n=10), Body fat% and Lean body mass% (n=8), Biochemical tests for Hb, Iron, Ferritin & Vitamin D (n=2), Performance times for 100m (n=7), 200m (n=7), External load metrics {Strength [1 RM hang clean, back squat, bench press, 3 RM Hip thrust, standing broad jump (m), counter movement jump (cm), squat jump (cm)] & track [standing 30m (s), flying 30m (s)]}, Ancillary metrics (subjective feedback, compliance) were periodically assessed over 11 months. The athlete recorded lowest body fat% [200m (8.8), 100m (8.1)], highest lean body mass% [200m (91.2), 100m (91.9)] and personal best performances at strength and track tests in the competition preparation phase, just before main competitions in April 22 for 200m & Aug 22 for 100m while clocking both fastest times [200m (20.52s), 100m (10.25s)] as well as creating national records in both. However, no differences were found between non-competition and competition phases and no association between body fat% with performance times, strength and track tests could be established at present due to insufficient data points, although, we hope that we are able to prove these trends over the next few years of the athletes’ career. This case study demonstrates an approach that periodizes nutrition strategies with training in an Indian set up to maximize training adaptations for the athlete to peak at the right competitions.

The Ease PMS Study - Effect of Specific Dietary Guidelines on Symptoms of Premenstrual Syndrome

Nurany N1, G Furniturewala1, J Shah1, S Gupta1

1Working with Rujuta Diwekar, Mumbai, India

A public health project was conducted for twelve weeks to gauge the effect of specific dietary guidelines on the symptoms of premenstrual syndrome (PMS). More than fourteen hundred participants took part in the observational study conducted over social media. Premenstrual syndrome is one of the most common disorders in women of reproductive age that could impact quality of daily life. It is a set of physical and psychological symptoms that start about five to ten days before menstruation and usually relieve or ease out once menstruation begins. PMS is becoming increasingly common in recent times. PMS symptoms effect multiple systems of the body, from gastrointestinal to reproductive. Given the varied nature of the symptoms of PMS, the line of treatment being used is typically based on symptomatic relief. Common medications prescribed include selective serotonin reuptake inhibitors (SSRIs), nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics and hormonal contraceptives. A big proportion of women undergoing PMS symptoms accept it as an inconvenience and continue with their daily life with the pain and other troubles. Certain time-tested traditional foods and eating practices have been used in India to help women alleviate the PMS symptoms. Based on these, three specific guidelines were given to the participants to incorporate in their daily lives, while keeping everything else the same. These were – a) Start your day with overnight soaked raisins and kesar (saffron strands), b) add a teaspoon of ghee (clarified butter) to all three main meals and c) have a banana as an evening snack. The participants self-reported their monthly progress on a scale of one to five, on six of the most common symptoms of PMS: mood swings, bloating and cramps, sugar cravings, breast tenderness, nausea, and constipation. At the end of twelve weeks, we noticed an improvement in the PMS symptoms as described in the table below. Public health messages should therefore focus on advocating local and traditional foods and time-tested eating practices as they provide an easy, economical, and culturally compliant method of improving PMS related symptoms, along with putting the individual in control of her own treatment.

Table – Ease PMS study, observed % improvement in PMS symptoms

Self-rating on scale of 1–5Mood swingsBloating and crampsSugar cravingsBreast tendernessNauseaConstipation
At start3.883.913.162.852.052.55
Month 12.782.872.372.051.591.99
Month 22.462.622.111.941.491.89
Month 32.302.421.911.711.461.85

A Case Study of the Challenges and Biases Arising in Cross-Sectional Studies of Outcomes Described By the Female and Male Athlete Triad and Relative Energy Deficiency in Sport Models

Rogers M1,2, N Vlahovich3, G Waddington1,2, M Drew3, L Burke4

1Australian Institute of Sport, Australia

2Research Institute for Sport and Exercise, University of Canberra, Australia

3Faculty of Health, University of Canberra, Australia

4Mary MacKillop Institute for Health Research, Australian Catholic University, Australia

The assessment of energy availability (EA) in free-living high-performance athletes is challenging and affected by inherent biases. Further, the models describing the outcomes of diseases associated with low energy availability (LEA) – the Female and Male Athlete Triad and Relative Energy Deficiency in Sport (RED-S) – do not fully incorporate clinical epidemiology principles thus limiting understanding of the phenomena resulting from exposure to LEA. The aim of this case study was to critically analyse the implementation of a previous research project and its associated dataset to identify a range of methodological challenges and biases often introduced in this field of research. A cross-sectional investigation of outcomes described in association with LEA was undertaken on Australian female athletes training at state or national level (age 15-32 y; mass 69.5 ± 10.3kg; body fat 23.1 ± 5.0%). Symptoms, clinical findings and laboratory investigations relevant to RED-S were assessed. Analysis was undertaken into the quantity and causes of missing data. Over one-third (37%) of invited participants declined, mostly due to logistics and scheduling conflicts. Within the components offered, missing data rates ranged from 5-56% with no component achieving total completion. Reasons for missing data varied and included reported needle phobia, illness on testing day, non-response, miscommunication in written or verbal test request, recognised error in data collection, unavailability of external laboratory for sample analysis, and decline by personal choice (no reason provided). Direct assessment of EA was intended but was hindered by low compliance and poor-quality data capture of the dietary component. Causes of reduced participation rates and missing data are likely to introduce a bias in identifying true prevalence for problematic issues. Identified biases included diagnostic suspicion, recall, unacceptability, misclassification, and differential reference. Studies should be transparent in reporting analyses of drop-out rates and missing and/or poor-quality data to identify potential biases in the complete dataset. This will support improved study designs, aid clinical interpretation of studies and improve treatment and prevention of LEA exposure and its associated disease outcomes.

Effects of the Japanese Diet on Post-Exercise Glycogen Resynthesis in Mice Skeletal Muscle and Liver

Koike A1, T Karasawa1, S Terada1

1Department of Life Science, Graduate School of Arts and Science, The University of Tokyo

The Japanese diet (JD) has been considered as an effective dietary strategy for athletes in Japan because it contains high amount of carbohydrate, which is the main fuel source during high-intensity exercise. After intense exercise, exhausted stores of endogenous carbohydrate (glycogen) need to be replenished by consuming high carbohydrate diet. Although the intake of the JD may promote post-exercise glycogen recovery, there is no evidence to support this hypothesis. The purpose of this study was therefore to examine the effect of the JD intake after acute exercise on glycogen accumulation in mice skeletal muscle and liver. In this study, male 8-week-old ICR mice performed 60-min running exercise to deplete glycogen and were then orally administered either the JD (PFC = 15.9:28.4:55.7) or Western diet (WD, PFC = 15.4:36.7:47.9). The JD and WD were prepared as follows: one-week menus (for 21 meals) of the JD and WD were created based on the National Health and Nutrition Examination Survey of each country, and then cooked. For making the diets liquid, one-week meals of each diet were mixed, ground and sonicated well. The volume of each diet administered was adjusted to provide equal levels of energy (30.9 kcal/ kg BW). Consequently, we found that at 2 h or 4 h after the administration, muscle and liver glycogen levels in the JD group were higher than that in the WD group (p< 0.01). In addition, the JD group had higher plasma insulin concentration than the WD group (p< 0.05) and there was a positive correlation between the plasma insulin level and the glycogen concentration. The phosphorylation state of Akt, which is known as a proximal signalling molecule of insulin signalling pathway, in skeletal muscle was also higher in the JD group than in the WD group (p< 0.05). These results suggest that the intake of JD after acute exercise may enhance muscle and liver glycogen recovery. Furthermore, this effect appears to be mediated by the increased insulin secretion and the activation of insulin signalling.

Decreased Pancreatic Amylase Activity After Acute High-Intensity Exercise and Its Effects on Post-Exercise Muscle Glycogen Recovery

Kondo S1,2,3, T Karasawa2,3, A Koike2, M Tsutsui2, J Kunisawa1, S Terada2

1Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, Collaborative Research Center for Health and Medicine, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Japan

2Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan

3Research Fellow of Japan Society for the Promotion of Science, Japan

We previously reported that an acute bout of endurance exercise for 6 h, but not 1 h, decreased pancreatic amylase activity, suggesting that acute endurance exercise affects carbohydrate digestive capacity in an exercise duration-dependent manner. In this study, we evaluated the effects of differing intensity of acute endurance exercise on pancreatic amylase activity in mice. Male C57BL/6J mice were subjected to acute bout of low- or high-intensity running exercise (Ex-Low: 10 m/min, Ex-High: 20 m/min, respectively) for 60 min. Sedentary mice served as a sedentary control. Immediately after the acute exercise, the Ex-High group, but not the Ex-Low group, showed lower total pancreatic amylase activity than the control group. To explore whether the high-intensity exercise-induced decrease in amylase activity affects post-exercise muscle glycogen recovery, we then assessed muscle glycogen synthesis rate in the Ex-High group mice orally administered either glucose or starch solution (2.0 mg/g BW) immediately after the exercise. Consequently, we found that post-exercise muscle glycogen resynthesis rate during 2-h recovery period was lower in the starch-fed mice than in the glucose-fed mice. In contrast, such difference in glycogen synthesis rate was not observed between starch- and glucose-fed mice in the sedentary control group (without performing exercise). In conclusion, these results may suggest that acute endurance exercise decreases pancreatic carbohydrate digestive capacity in an exercise intensity-dependent manner, resulting in delayed post-exercise muscle glycogen resynthesis when polysaccharides are ingested.

Dose-Response Effect of Pre-Exercise Protein Ingestion on Fat Oxidation and Energy Intake

Peeters WM1, LE Cook1, O Page1

1School of Biomedical, Nutritional and Sport Sciences, Newcastle University, England

Fasted exercise is employed by exercisers aiming to increase fat oxidative capacity. Pre-exercise protein ingestion might maintain similar fat oxidation rates compared to fasted exercise, but it is unknown if there is a dose-dependent response. This was a double-blinded randomised within-subject study design. After an overnight fast, ten healthy active individuals (6 males, 4 females, age: 25 ± 3 y, height: 173 ± 11 cm, weight: 72.6 ± 14.1 kg, VO2max: 48.6 ± 10.8 ml/kg/min) performed one hour of cycling at 60% of their peak power, thirty minutes after having consumed either 0, 20 or 40 g of whey protein hydrolysate. Indirect calorimetry was used to measure substrate oxidation every 15 min of exercise and to measure resting energy expenditure before protein ingestion and 45 min post-exercise. Rate of perceived exertion (RPE) during exercise was used as a subjective outcome. Participants recorded their food intake for the rest of the day. Outcomes are Mean±SEM. Fat oxidation increased over time during exercise (0.22 ± 0.06, 0.31 ± 0.06, 0.41 ± 0.06, 0.42 ± 0.07 g/min at 15, 30, 45 and 60 min respectively; p = 0.000), but no overall treatment (0 g = 0.34 ± 0.07, 20 g = 0.29 ± 0.06, 40 g = 0.39 ± 0.08, g/min p = 0.16) or interaction effect (p = 0.32) was observed. Resting energy expenditure was higher after exercise (pre = 2087 ± 195 vs. post = 2404 ± 220 kcal; p = 0.003), but no interaction effect with treatment was present (p = 0.56). Overall RPE during exercise did not differ between treatments (p = 0.48). Energy intake after trials did not differ between treatment (0 g = 1989 ± 318, 20 g = 1823 ± 299, 40 g = 1961 ± 399 kcal; p = 0.69). Consumption of protein before exercise seems to maintain fat oxidation rates compared to fasted exercise and might be considered as a feeding strategy for exercisers who aim to enhance fat oxidative capacity but struggle to incorporate fasted training into their program.

Effect of Turmeric Supplementation on Markers of Recovery in Elite Footballers: A Pilot Study

Clayton DJ1, R Burbeary2, PJ Hennis1, RM James1, C Saward1, A Colledge1, R Scott1, R McMahon3, I Varley1

1Musculoskeletal Research Group, School of Science and Technology, Nottingham Trent University, UK

2Lincoln City Football Club, LNER Stadium, Lincoln

3Rotherham United Football Club, AESSEAL New York Stadium, Rotherham

Football match-play causes muscle damage and provokes an inflammatory response. Rapid recovery following match-play is paramount to optimising performance levels and reducing injury risk. Curcumin is a dietary compound that has been shown to reduce muscle damage and soreness post-exercise, which is found in high concentrations in turmeric. This pilot study explored whether a turmeric supplement could improve markers of recovery in elite male footballers. Baseline measurements of subjective leg and whole-body soreness, isometric mid-thigh pull (IMTP) and counter movement jump (CMJ) performance, and plasma concentrations of inflammatory markers creatin kinase (CK) and C-reactive protein (CRP), were collected after 96 h of inactivity. Twenty-two male elite footballers were then randomised to either consume a 60mL commercially available turmeric drink twice per day (Raw Turmeric Original Shot, The Turmeric Co., UK), or to a control group who did not consume the product. Following eight competitive matches, soreness and inflammation markers were assessed immediately (0 h), 40 and 64 h post-match. IMTP and CMJ were assessed 40 and 64 h post-match. Percentage change from baseline was calculated for each marker at timepoint. Two-way ANOVAs examined the effect of turmeric supplementation (group), timepoint, and their interaction, on change in each marker, followed, where appropriate, by Bonferroni-corrected post-hoc tests. Data are presented as mean±standard error. There were main effects of group (P< 0.05) and time (P< 0.01), but no interaction effect (P> 0.29), for leg and whole-body soreness. Leg soreness was 77 ± 36 % lower (P< 0.05) and whole-body soreness was 106 ± 37 % lower (P< 0.01) following turmeric supplementation. Leg and whole-body soreness were also lower at 64 h than at 0 h (P< 0.001). There were no main effects of group (P=0.13) or time (P=0.08), but there was an interaction effect (P< 0.05), for CRP. CRP was 1082 ± 447 % lower at 72 h following turmeric supplementation than control (P< 0.05). There were no main effects of turmeric supplementation on CK, CMJ or IMTP. Turmeric supplementation lowered soreness and CRP, suggesting turmeric may attenuate fatigue post-match play in elite footballers. This was an applied study in a small cohort, but these findings provide scope for further research.

Self-Reported Methods of Weight Cutting in Professional Jockeys: What are the Current Weight-Making Practices?

Dunne A1, G Warrington2,3, A McGoldrick4, J Pugh4, G O’Loughlin4, M Harrison1, SJ Cullen1

1Department of Sport & Exercise Science, South East Technological University

2Department of Physical Education and Sport Science, University of Limerick

3Sport and Human Performance Research Centre, Health Research Institute, University of Limerick

4Irish Horseracing Regulatory Board

Strategies for weight cutting (WC) in horse racing can vary, yet principally the methods are reliant and influenced by social and cultural practices more so than scientific evidence-based strategies. Despite the introduction of nutrition and exercise strategies for safe weight-making practices, there has been no update on the methods and frequency of WC in professional jockeys in Ireland since 2011. Therefore, the aim was to provide an update on the WC practices of Irish professional jockeys. A validated health and lifestyle questionnaire previously issued amongst jockeys (Dolan et al., 2011) was completed by 85 male professional jockeys (flat n=39; national hunt (NH) n=46). The questionnaire was administered in a semi-structured interview format to record weight-making practices, including methods and frequency of WC and magnitude of weight cut before racing. Descriptive and non-parametric statistics were used to compare the WC practices of flat and NH jockeys. Large individual variations (0 – 6.4 kg) were apparent in the results obtained for the greatest amount of weight cut before racing, with NH jockeys cutting more weight than flat jockeys (2.5 ± 1.4 kg vs 3.6 ± 1.3 kg, flat and NH respectively). Frequency of WC found flat jockeys were more likely to cut weight daily (18% vs 4%) for racing than NH jockeys, while there was no difference for weekly (23% vs 33%) WC. Sauna (75% vs 94%), wearing a sweatsuit (67% vs 70%), hot baths (69% vs 78%) and excessive exercise (50% vs 52%) were the most popular methods for WC in flat and NH jockeys respectively. Laxatives (6% and 11%) and self-induced vomiting or flipping (0% vs 4%) continue to be used as acute weight loss techniques, flat and NH, respectively. NH jockeys use sauna and flipping for WC more than flat jockeys. While NH jockeys cut weight less frequently, findings indicate the body mass reduction is greater than flat jockeys, which may have negative performance consequences. Results from this study show methods for WC are consistent with those reported in 2011, with trends suggesting NH jockeys employ a greater range of WC techniques than flat jockeys. Given the lack of change in weight-making practices by jockeys with a reliance on acute WC, additional weight management supports, and individualised minimum riding weights are urgently needed.

New Zealand Blackcurrant Extract Enhances Skeletal Muscle Glycogen Re-Synthesis in Response to Sub-Optimal Carbohydrate Ingestion

Fortis HO1, Jones RO1, Hearris MA1, Barrett JS1, Jones LO1, Morton JP1, Strauss JA1, Shepherd SO1

1Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom

Endurance athletes often train multiple times per day, thus requiring considered recovery strategies with a particular focus on replenishing muscle glycogen stores. Current guidelines state a carbohydrate intake of 1.2 g·kg body mass-1·h-1 following exercise in order to maximise glycogen synthesis, yet in practice many athletes do not achieve this. Anthocyanin-rich New Zealand blackcurrant (NZBC) extract improves glucose clearance following carbohydrate intake, while cell culture models show anthocyanins to augment glucose transport and cellular uptake. Therefore, we investigated whether 7 days of NZBC extract supplementation could enhance skeletal muscle glycogen resynthesis in response to sub-optimal carbohydrate intake. In a randomised, cross-over, double-blind, placebo-controlled design, eight moderately-trained males (55.6 ± 7.0 ml·min-1·kg-1) ingested 600 mg·day−1 NZBC extract or placebo (600 mg·day−1 microcrystalline cellulose; PLA) for 7 days. Participants completed a glycogen-depleting bout of exercise on the evening of day 6 and were provided with a low carbohydrate evening meal. The next morning, participants performed 45 min of moderate-intensity cycling (50% of peak power output [PPO]) followed by an exercise capacity test (1 min intervals alternating between 80% and 40% PPO). Following exercise, participants consumed maltodextrin (0.8 g·kg-1·h-1) for 4 h, and muscle biopsies were collected at 0, 1 and 4 h post-exercise. Muscle glycogen concentrations increased throughout recovery in both conditions (P< 0.001). However, after 4 h of recovery muscle glycogen concentrations were greater in response to NZBC supplementation (258 ± 34 mmol·kg-1 dw) than PLA (236 ± 29 mmol·kg-1 dw; P=0.005). Accordingly, the net glycogen synthesis rate was greater (P=0.047) following NZBC (47 ± 10 mmol·kg dw-1·h-1) than PLA (42 ± 10 mmol·kg dw-1·h-1; P=0.047). In summary, short-term NZBC extract supplementation shows promise as a nutritional adjunct to carbohydrate intake to enhance the rate of muscle glycogen replenishment following exercise, particularly in the face of sub-optimal carbohydrate consumption. Future work will determine the impact of this nutritional strategy to improve performance, and explore potential mechanisms underpinning the observed data.

New Zealand Blackcurrant Extract Enhances Whole-Body Fat Oxidation But Does Not Affect Intramuscular Triglyceride Utilisation In Human Skeletal Muscle

Jones L, L Leung1, JS Barrett1, HO Fortis1, JA Strauss1, SO Shepherd1

1Research Institute for Sport and Exercise Sciences, Liverpool John Moores University

Blackcurrants are a food source rich in polyphenols, including a number of flavonoids known as anthocyanins, which have been associated with improvements in physiological and metabolic parameters. Anthocyanin-rich New Zealand blackcurrant (NZBC) extract has previously been shown to increase rates of whole-body fat oxidation during prolonged exercise, but the mechanisms underpinning this finding are yet to be resolved. To begin to address this, we examined whether short-term NZBC extract supplementation would increase intramuscular triglyceride (IMTG) utilisation and influence lipid droplet (LD) morphology during prolonged exercise. In a randomised, crossover, double-blind design, ten moderately-trained males ingested 600 mg·day−1 NZBC extract or placebo (PLA) for 7 days. On day 7, participants performed 120 min cycling at 65% VO2max followed by an exercise capacity test (time-to-exhaustion at 150% lactate threshold). Muscle biopsies were obtained at 0, 30 and 120 min of submaximal cycling. Each experimental trial was commenced after a ∼36 hours carbohydrate loading protocol and pre-exercise meal (∼9 and ∼2 g·kg- 1, respectively). Exercise decreased IMTG content (type I fibres ∼35%; type II fibres ∼24%; P < 0.001), which was attributed to decreases in both LD number (P = 0.010) and size (P = 0.004), but there was no difference between conditions (all; P > 0.05). Plasma NEFA and glycerol concentrations increased during exercise (P < 0.001), with no difference between conditions (P > 0.05). NZBC extract tended to increase exercise capacity (217 ± 104 s) compared to PLA (156 ± 83 s; P = 0.081). Whole-body fat oxidation was ∼24% greater following NZBC extract supplementation than PLA (P = 0.025), which is in agreement with several previous studies. Our data now suggest that the increase in fat oxidation occurs in the absence of increased IMTG utilisation or greater concentrations of blood markers of adipose tissue lipolysis. This suggests that other factors are mediating the increase in whole-body fat oxidation observed following short-term supplementation with NZBC extract (e.g. increased delivery and/or uptake of NEFA into skeletal muscle). The observed improvement in exercise capacity test could be due to a possible glycogen sparing effect which merits further investigation.

10 Minutes of Sitting is Sufficient to Overcome the Effects of Postural Change (Walking to Sitting) on Blood and Plasma Volume and Osmolality

Reynolds KM1, Rowland SN1, Bailey SP1, Funnell MP1, Mears SA1, James LJ1

1School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom

Activity and changes in posture have haemodynamic effects on blood/plasma volume (BV/PV), which may impact measured haematological, metabolic, or endocrine markers. Previous studies report increases in BV/PV when moving from standing to lying supine, stabilising within ∼20 min. Given blood samples are often taken in an upright seated, rather than supine position in research, clinical and anti-doping settings, understanding time course changes after sitting is important. Conversely, activity decreases BV/PV and a walk to blood sampling locations may have an effect on sample data. There are implications as the sampling process could be challenged especially with anti-doping. Thus, we examined the transition from walking to sitting on BV/PV, to capture maximal possible changes. Healthy males (n=8) and females (n=7) (25 ± 1 y, 1.73 ± 0.12 cm, 72.7 ± 14.9 kg) completed the study. Participants arrived overnight fasted (no food or fluid), having avoided strenuous exercise that morning. A 20-gauge cannula was inserted into a forearm vein and participants then rested in a standing position for 20 min before walking on a treadmill at 4 km/h for 20 min. After walking, participants assumed an upright seated position (within 7 ± 1 s), with blood samples (9 ml) drawn at 0, 5, 10, 20, 30 and 40 minutes after sitting. Blood haemoglobin and haematocrit (to estimate changes in BV/PV), and plasma osmolality were determined. The cannula was flushed with 9 mL sterile saline after sampling. Data were normally distributed and analysed using one-way repeated measures ANOVA, followed by paired t-tests. Time points were compared to 40 min with no correction for multiple comparisons. Compared to 40 min, PV was lower at 0 min (-6.5 ± 3.2%; P< 0.001) and tended to be lower at 5 min (-1.8 ± 3.1%; P=0.051). Similarly, compared to 40 min BV was lower at 0 min (-3.9 ± 2.6%; P< 0.001) and tended to be lower at 5 min (-1.4 ± 2.3%; P=0.074). Conversely, plasma osmolality was higher at 0 min (289 ± 3 mosmol/kg; P=0.009) and 5 min (0.289 ± 0.003 mosmol/kg; P=0.018) than 40 min (287 ± 3 mosmol/kg). The data shows stabilisation of PV/BV after 10 min of sitting and offers an appropriate timeline for consistent blood sampling be it in research, clinical and/or anti-doping settings.

The Effect of Nutrition and Genetics on Musculoskeletal Injury in Contact Sports: A Systematic Review

Lucas F1,2,3, V Iatridi1,2, R Costello4, C Graham5, C Curtis6, A Delaxtrat1

1Department of Sport, Health Sciences and Social Work, Oxford Brookes University, Oxford, UK

2Oxford Brookes Centre for Nutrition and Health, Oxford, England

3Centre for Movement, Occupational and Rehabilitation Sciences (MOReS), OxINMAHR, Oxford Brookes University, Oxford, UK, England

4Centre for Sport, Exercise & Life Sciences, Coventry University, England

5Cereneo Foundation, Switzerland

5Crystal Palace Football Club, England

To date, how diet can ameliorate musculoskeletal injury (MSKI) has focussed chiefly on contact sports male athletes. This systematic review aims to determine nutritional- and genetic-related risk factors in relation to MSKI in contact sports with a focus on exploring potential differences by gender. The review was conducted according to the Cochrane handbook and PRISMA principles and is registered with PROSPERO, number CRD42022318890. Peer-reviewed randomised controlled trials (RCTs) and cross-sectional studies with professional and recreational athletes aged between 18 and 44 years from football/soccer, rugby and handball were included. Medline, PubMed, SportDiscus, Embase, CINHAL, and Web of Science were searched from November 2021 to February 2022. The quality of the evidence was assessed with the Cochrane risk of bias tool and critical appraisal tool for RCTs and cross-sectional studies, respectively. 14 studies (n=443) were eligible for review covering exercise-induced muscle damage (EIMD) (n=10), injury rate (n=3), and bone health (n=1). Five dietary interventions positively affected EIMD. With injury rate, creatine supplementation led to fewer injuries than a placebo (p < 0.001). Two out of the 14 studies focused on female athletes (n=43). One assessed the Mediterranean diet and bone health: non-significant correlations between diet adherence and bone ultrasound attenuation (r2=-0.079, p > 0.05) or speed of sound (r2 =0.001, p> 0.05) were made. The second study assessed nutrient intake and muscle damage. Athletes complying with daily recommended intakes for nutrients had lower concentrations of creatine kinase pre-match (carbohydrate (146 ± 68 vs. 116 ± 22 U/l, p< 0.01), fibre (148 ± 67 vs. 112 ± 24 U/l, p< 0.01), vitamin B1 (235 ± 85 vs. 135 ± 57 U/l, p< 0.001), and chromium (191 ± 86 vs. 131 ± 52 U/l, p< 0.05). Across all studies, a range of nutritional strategies were employed to mitigate the risk of MSKI with equivocal results. No research paper had a cohort of both men and women or explored the influence of genetics and nutrition on MSKI. Further research is recommended into how genetics and nutritional intake may affect MSKI in female contact sports.

Use of Supplements and Medications by Athletes at the 2022 Birmingham Commonwealth Games

Statham L1, AL Pipe2, P Harcourt3

1Warwick Medical School, University of Warwick, Coventry, United Kingdom

2Division of Prevention and Rehabilitation, University of Ottawa Heart Institute, Ottawa, Ontario, Canada

3Commonwealth Games Federation. With permission and support from the CGF

While supplement and medication use are widespread in the general population, elite athletes have been reported to have a higher prevalence, with reasons for use including performance optimisation, managing nutritional deficiencies, and prevention of illness and injury. Some substances may carry benefits but others may degrade performance and cause harm. Contamination of supplements is also the source of many adverse analytical findings in doping control procedures and may result in the application of sanctions. This research aims to identify the prevalence of supplement and medication use at the 2022 Birmingham Commonwealth Games. Athletes completed a self-report questionnaire regarding supplements and medications brought to the games at the Birmingham Commonwealth Welcome Centre at the National Exhibition Centre and athletes’ villages. Participants were a subset of 402 athletes competing at the Games, from 35 nations and representing 23 sports. 43% of athletes reported at least 1 supplement and 47% reported at least 1 medication. The most reported supplements included protein (19%), multivitamins (15%), and electrolytes (12%) and the most used medications were NSAIDs (26%) and Other Analgesics (24%). The use of supplements and medications by athletes varied by sport and country. The level of supplement use does not reflect the evidence base regarding their efficacy, indicating the need for further nutritional education.

Effect of Carbohydrate Supplementation on Endocrine and Muscle Glycogen Contents in Amenorrhoeic Runners

Kamei A1, E Takai1, Y Ishii1, E Kondo2,3, M Nakamura1, H Takahashi1,3, S Nose-Ogura4

1Japan Institute of Sports Sciences, Japan

2Japan Society for the Promotion of Science, Japan

3Faculty of Health and Sport Sciences, University of Tsukuba, Japan

4Department of Obstetrics and Gynecology, University of Tokyo, Japan

The aim of this study was to investigate whether difference of menstruation status affects change in body weight (BM) and composition, muscle glycogen (mGly) concentration, and blood parameters with carbohydrate supplementation. The participants were 12 female middle- and long-distance runners (eumenorrhea; n = 6, mean±SD age 23 ± 3 y, BMI 19.0 ± 1.7 kg/m2, amenorrhea; n = 6, age 19 ± 2 y, BMI 17.7 ± 0.8 kg/m2). This study consisted of 1 day for the preliminary survey and 4 days for the experiment. The preliminary survey was conducted about one month before the main survey. The participants visited the laboratory on the evening of the first day, and were allowed to take the prescribed meal and ad-libitum water and to participate to normal training until end of study. The prescribed meal of the second day contained the macronutrients based on the preliminary survey, and the prescribed meal of the third day was added 2 g/kg BM/d of carbohydrate to the amounts of macronutrients on the second day. BM, body composition, and mGly concentration were measured every morning. Blood sample was collected at day-2 and day-4. The mGly concentration in the calf of the right leg were measured using 13C-magnetic resonance spectroscopy (MRS). In addition, physical activity and dietary intake were recorded throughout the study, and energy availability was calculated from energy intake, energy expenditure during exercise and fat-free mass. In the eumenorrhea group, the change in mGly concentration from day-3 to day-4 recovered to 100.5 ± 15.1%, recovered only 79.8 ± 27.8% in the amenorrhea group. Luteinizing hormone in the amenorrhea group increased after carbohydrate supplementation in four of six participants, decreased in one participant, and did not change in one participant with a low level of 0.11 mIU/ml before supplementation. In conclusion, mGly concentration in amenorrhea runners did not recover adequately with 2 g/kg BM/d of carbohydrate supplementation. However, some amenorrhea runners showed an increase in luteinizing hormone, speculating the increased luteinizing hormone as per carbohydrate supplementation could stimulate estrogen and progesterone, and contribute to recover the menstrual cycle.

Effects of Supplementing Zinc-Magnesium Aspartate on Sleep Quality and Submaximal Weightlifting Performance, Following Two Consecutive Nights of Partial Sleep Deprivation (4 h per Night)

Gallagher C1, V Austin1, KW Taylor1, J Dally1, J Jacques1, S Pullinger2, N Walsh1, B Edwards1

1Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK

2Sport Science Department, Inspire Institute of Sport, Vidyanagar, Dist. Bellary – 583275

This study examined whether supplementing zinc-magnesium aspartate (ZMA), while under conditions of partial sleep deprivation (4h sleep over two consecutive nights), was beneficial on sleep quality and subsequent day (07:00 h and 17:00 h) submaximal weightlifting performance. Seventeen resistance trained males participated (22 ± 2 years; 177 ± 5 cm; 76 ± 11 kg), with 7 of the participants completing 3 conditions: ZMA supplementation with 4 hours sleep (ZMA), placebo supplementation with 4 hours sleep (PLA), or a no pill control condition with 4 hours sleep (NP), with the remaining 9 participants only completing ZMA and PLA conditions. 1 repetition max (1RM) bench press and back squat, habitual sleep and food intake were recorded, as well as completion of two familiarisation sessions. The study was a randomised, double blinded, placebo-controlled trial and all conditions were separated by 7 days, with trial order being randomised and counterbalanced. Resting tympanic temperature, Profile of Mood States and Stanford Sleepiness questionnaires were recorded at four time points (07:00, 11:00h, 14:00, 17:00 h) on the day of testing protocol. An active warm up was then performed, followed by three repetitions of left- and right-hand grip strength. The submaximal exercise session then commenced, which consisted of three repetitions at 40, 60 and 80% of 1RM for bench press and back squat. Performance measures were recorded using Muscle Lab linear encoders that were attached perpendicular to the Olympic bar. Data was analysed using a general linear model with repeated measures. No main effect for condition was found for any Muscle Lab variables, yet RPE, muscle fatigue, breathing and perceived exertion increased in line with load on the bar. A trend was observed for breathing values, for both bench press (P = 0.069) and back squat (P = 0.058) and time to peak velocity (P = 0.095). We reported no main effect for condition for all actimetry data and sleep questionnaires, except the Stanford Sleepiness Questionnaire, which demonstrated an interaction (P = 0.010). In summary, supplementation of ZMA for 2 nights of consecutive partial sleep deprivation (4 h per night), has demonstrated no effect on sleep quality or subsequent day submaximal weightlifting performance.

Indicators of Exercise Addiction Are Increased in Female Athletes At Risk For Low Energy Availability

Wasserfurth P1, D Toepffer1, H Engel1, K Kirchner1, R Halioua2, M Claussen2, K Koehler1

1Department of Sport and Health Sciences, Technical University Munich, Germany

2Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, Switzerland

Relative energy deficiency in sports (RED-S) is centered by chronic low energy availability (LEA), with a bidirectional causative relationship with mental health. Aside the well-established link between eating disorders and LEA, exercise addiction (ExA) has been proposed as another independent LEA risk factor. The aim of this investigation was to assess the relationship between LEA, eating disorders, ExA and biomarkers indicative of LEA in a sample of female endurance athletes. In a cross-sectional study, 23 athletes (27 ± 6 yrs, BMI 20.6 ± 2.0 kg/m2) who train ≥ 4 times/week completed the Low Energy in Females Questionnaire (LEAF-Q), the Brief Eating Disorder in Athletes Questionnaire (BEDA-Q), and an expanded version of the Exercise Addiction Inventory (EAI). Biomarkers of LEA included a reduction in resting metabolic rate, defined as a ratio of measured and predicted RMR < 0.9 and reduced circulating concentrations of triiodothyronine (T3). According to the LEAF scores, 52% of all athletes were at risk of LEA. Athletes at risk for LEA demonstrated a higher risk for eating disorders (42% vs. 9%) and exercise addiction (ExA; 25% vs. 0%), which was predominantly (67%) categorized as secondary ExA. Overall, EAI scores were increased in athletes at risk for LEA (22.4 ± 3.7 vs 18.9 ± 2.7, p=0.014), and more of those athletes reported to train despite pain or injury (42% vs. 18%). Additionally, athletes at risk for LEA were more likely to have suppressed RMR and low T3 (42% vs 36% and 17% vs. 9% respectively). EAI scores were not associated with LEA biomarkers. Our findings indicate that the inclusion of exercise addiction could complement the LEAF-Q when screening athletes for LEA. Given that mental health and LEA are bidirectional, early detection of compromised mental health could aid in prevention of chronic LEA and RED-S. Acknowledgements: This study was funded by the Robert-Enke-Foundation.

Total and Free 25-Hydroxyvitamin D Levels are Associated With Bone Mineral Density in Adolescent Athletes

Granda D1, J Malczewska-Lenczowska1, O Surała1, B Szczepańska1

1Department of Nutrition Physiology and Dietetics, Institute of Sport, National Research Institute, Warsaw, Poland

Vitamin D plays an important role in calcium and bone homeostasis. In the circulation most 25-hydroxyvitamin D (25OHD) is bound to vitamin D-binding protein (VDBP) or albumin. The remaining small proportion of unbound vitamin D is the free form (f25(OH)D). According to the “free hormone” hypothesis, f25(OH)D does reflect its biological actions better than commonly used t25(OH)D. We hypothesized that f25(OH)D may better correlate with bone density than t25(OH)D in healthy adolescent subjects. The study included 50 healthy adolescent males (25 ski jumpers (SJ) and 25 non-athletes (NA)), aged 16.0 ± 0.1 and 17.4 ± 1.1 years, respectively. t25(OH)D and f25(OH)D (ELISA, DiASource) were determined in serum and bone mineral density (BMD) were assessed in femur neck and lumbar spine (L1-L4) (DXA, Lunar Prodigy). In the whole group subjects with low bone density (Z-score ≤-1) constituted of 18.0% in both studied bone areas - there were no differences between the groups (p> 0.05). The mean concentrations of t25(OH)D and f25(OH)D were higher in SJ than NA (t25(OH)D: 29.3 ± 8.4 ng/ml vs 20.4 ± 4.5 ng/ml, p< 0.001; f25(OH)D: 6.8 ± 1.9 pg/ml vs 5.2 ± 1.6 p=0.003, respectively). Values of t25(OH)D ≤ 30 ng/mL were taken as deficit or insufficient levels. Accordingly 86% of subjects (SJ=76%; NA=100%) were qualified as deficiency/insufficiency and only 11.8% (SJ=24%; NA=0%) as sufficiency. Regardless of the t25(OH)D status no differences were found in mean BMD values between the SJ and NA group (T-student test). However, when vitamin D status was assessed with f25(OH)D, there was a difference between SJ and NA group in the femur neck BMD Z-score among vitamin D insufficient subjects (mean BMD Z-scores in SJ and NA respectively: -0.61 ± 1.18 vs 0.49 ± 1.16, p=0.049). In the athletes there was a moderate positive correlation between t25(OH)D and femur neck (r=0.403) and L1-L4 (r=0.431) BMD Z-score, and between f25(OH)D and L1-L4 BMD Z-score (r=0.485). No similar correlations were observed in NA group. Presented results confirm that both the t25(OH)D and f25(OH)D are associated with bone mineral density, but mainly in the athlete population. The f25(OH)D does not seem superior to t25(OH)D in predicting risk of low bone density in adolescent.

Formulation of an Isonitrogenous Negative Control for Human Feeding Studies Measuring Muscle Protein Synthesis

Norton C1,2,3,4, BP Carson1,2,4, M Amigo-Benavent2,4,5, RW Davies4,6, PM Jakeman1,2,3

1Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX, Limerick, Ireland

2Health Research Institute, University of Limerick, V94 T9PX, Limerick, Ireland

3Sport and Human Performance Research Centre, University of Limerick, V94 T9PX, Limerick, Ireland

4Food for Health Ireland, Science Centre South (S2.79), University College Dublin, Dublin 4, Ireland

5Department of Biological Sciences, University of Limerick, V94 T9PX, Limerick, Ireland

5Chester Medical School, University of Chester, University Centre Shrewsbury, Shrewsbury, United Kingdom, SY3, UK

The ability of protein to enhance muscle protein synthesis (MPS) is of great interest in human health and disease. The bioactivity of proteins to regulate MPS resides, principally, with the essential amino acid (EAA) composition and the temporal pattern of postprandial EAA hyperaminoacidaemia. Feeding and digestion are complex physiological processes that effect a change in MPS independent of that ascribed to protein, so null comparators are difficult to devise. Current practice centres on non-nitrogenous, isoenergetic equivalents (e.g. carbohydrate) that may not be an appropriate control for human feeding studies. The aim of this research was to design an isonitrogenous amino acid (AA) formulation for use as a negative control (i.e. non-bioactive) in the study of protein ingestion on MPS. Milk-derived proteins (MDP) provided the reference protein and AA content for the null formulation. EAAs, sulphur-containing and functional amino acids (fAA) were removed and replaced by the residual amino acids enhanced in proportion to their reference composition. Based on a 0.33g.kg-1 body mass dose, the final amount of each AA was within tolerable upper limits (UL) of intake. Our results show the protein and AA content of the control formulation was equal to the MDP reference at an administered dose of 0.33g·kg-1 BM (body mass). We confirm absence of any postprandial bioactivity in vitro (cell culture) and in vivo (human) experiments. We conclude that this novel AA formulation advances methodologies for use in investigating the role of protein feeding on MPS and may act as a viable negative control in human feeding studies.

Relationship Between Water Turnover and Body Composition, Training Time, and Environment in Judo Athletes During the Summer Training Season

Kondo E1,2,3, A Uchizawa2,4, H Hiraoka1, H Okada1, K Watanabe1, Y Tanabe2,5, M Kosugi6, A Ito6, H Takahashi1,7, Y Higaki6, AM Silva3, H Sagayama1

1Faculty of Health and Sport Sciences, University of Tsukuba

2Japan Society for the Promotion of Sciences

3Faculty of Human Kinetics, University of Lisbon

4Graduate School of Comprehensive Human Sciences, University of Tsukuba

5Faculty of Health and Sports Sciences, Toyo University

5Faculty of Sports and Health Science, Fukuoka University

7Advanced Research Initiative for Human High Performance, University of Tsukuba

Establishing water requirements in Judo athletes is important to maintain conditioning and make weight for competitions. Adequate fluid intake, especially during the summer training season, also contributes to reducing the risk for heat-related illness. Water turnover (WT) varies widely across inter-individual athletes through factors such as body size and composition, training time, and environmental factors. Daily water requirements, including water from meals, are estimated according to WT using stable isotope techniques. This study aimed to clarify the relationship among WT and body size and composition, daily training time, and environment in Judo athletes during the summer training season. Twenty-six Judo athletes (21 male, 5 female) underwent 7-day WT measurement using a stable-isotope dilution technique and body composition as per a three-component model involving body density from air displacement plethysmography (fat, total body water, and residual mass). Body surface area was estimated using Dubois and Dubois’s estimation equation. The athletes recorded their training time during the WT measurement. Mean (± SD) WT was 5.8 ± 1.8 L/day (range, 3.1–11.0 L/day). WT correlated with height (r = 0.667), body mass (r = 0.510), body volume (r = 0.439), body surface area (r = 0.598), residual mass (r = 0.514), training time (r = 0.433), and ambient temperature (r = 0.417). In contrast, there was no relationship with body mass index, body density, fat mass, and relative humidity. Body surface area showed the strongest relationship with WT (β = 0.897, p < 0.001) as per stepwise multiple regression analysis using training time (β = 0.395, p = 0.001) and body density (β = 0.290, p = 0.039) as independent variables; body surface area, training time, and body density accounted for 72.5% of the total variation in WT. In conclusion, WT in Judo athletes during the summer training season could be estimated using body surface area, training time, and body density. We speculate that body water loss through evaporation from the body surface and perspiration could be affected by daily WT.

The Effect of a Low or High Carbohydrate Meal Prior to Exercise on Markers of Bone Metabolism in Endurance Athletes

Raleigh C1,3, S Madigan1,3, C Sinnott-O’Connor3, C Sale4, C Norton1,2, BP Carson1,2

1Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX, Limerick, Ireland

2Health Research Institute, University of Limerick, V94 T9PX, Limerick, Ireland

3Sport Ireland Institute, Sport Ireland Campus, Abbottstown, Dublin 15, D15 Y52H

4Institute of Sport, Manchester Metropolitan University, 99 Oxford Road, Manchester, M1 7EL, UK

Low carbohydrate dietary practices have gained increased attention in recent times with many endurance athletes, researchers and coaches advocating adopting this strategy to augment endurance phenotypic adaptation. However, recent evidence suggests that maintaining high carbohydrate availability across a training day that includes multiple sessions may attenuate the bone resorptive response to vigorous physical activity independent of energy availability. Therefore, our aim was to determine how a single pre-exercise energy and protein matched meal that is either low carbohydrate high fat (LCHF) or high carbohydrate low fat (HCLF) prior to a standardised bout of exercise could influence bone metabolic biomarkers. Four male participants (age 28 ± 6 y, height 1.76 ± 0.01 m, body mass 72.5 ± 5.7 kg, VO2max 68.2 ± 7.3 ml.min-1.kg-1) completed 2 hours of running at 70% VO2max on 2 separate occasions with blood samples collected in the fasted state, 1 hour after feeding, immediately, 1, 2, 3 and 4 hours after exercise for the measurement of carboxyterminal telopeptide (β-CTX) as an indicator of bone resorption and procollagen-1 N-terminal peptide (P1NP) as an indicator of bone formation. HCLF (1.5 g.kg BM-1 CHO, 0.4 g.kg BM-1 PRO and 0.1 g.kg BM-1 FAT) and LCHF (0.1 g.kg BM-1 CHO, 0.4 g.kg BM-1 PRO and 0.9 g.kg BM-1 FAT) Conditions were administered in a randomised, counterbalanced, crossover fashion. Baseline concentrations were compared using a paired samples t-test. Data were analysed using a two-way repeated measures ANOVA with a Tukey post-hoc test. There was no difference between conditions in baseline concentrations of β-CTX (p = .154) or P1NP (p = .299). There was a main effect of time for both β-CTX (F(6,18) = 5.95, p = 0.001) and P1NP (F(6,18) = 7.52, p < 0.001) but no main effect of condition or the interaction of time and condition. These data demonstrate that bone metabolism is sensitive to both feeding and vigorous exercise. However, preliminary analysis of four participants is insufficiently powered (45%) to definitively answer the effect of condition at this stage. Using the data collected here it is estimated that 16 participants will be required to provide 80% statistical power to establish an interaction effect or not on β-CTX concentration.

Prevalence of Low Carbohydrate Dietary Practices and Fasted Training in Elite Endurance Athletes and Associations With Bone Injury Incidence

Raleigh C1,3, S Madigan1,3, C Sinnott-O’Connor3, C Sale4, C Norton1,2, BP Carson1,2

1Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX, Limerick, Ireland

2Health Research Institute, University of Limerick, V94 T9PX, Limerick, Ireland

3Sport Ireland Institute, Sport Ireland Campus, Abbottstown, Dublin 15, D15 Y52H

4Institute of Sport, Manchester Metropolitan University, 99 Oxford Road, Manchester, M1 7EL, UK

Low carbohydrate (CHO) diets can present as an attractive dietary modification to endurance athletes due to purported benefits to the endurance phenotype. This approach, however, may increase the risk of low energy availability which can influence bone stress injury risk. Recent evidence also suggests that sub-optimal CHO intakes may also mediate bone metabolism independently of energy availability. This study aimed to investigate the prevalence of reduced CHO intake and fasted training in elite endurance athletes; and examine potential associations with bone injury incidence using a self-reported questionnaire. Eligible participants were endurance athletes aged 18- 35, who trained for a minimum of 8 hours per week and had competed at national championships event at a minimum. The questionnaire was designed specifically to fulfil the aims of this research and sampling was both purposeful and snowball. Of the 327 eligible respondents, 94 (29%) reported currently reducing their CHO intake over a period of weeks to months and 125 (38%) reported engaging in fasted training. Bone fractures and bone stress injuries were reported by 114 (35%) participants during their career. The most common type of injury was a fracture (n= 100), the most common cause of injury was overuse or overload (n= 56) and the most common area of the body was the foot (n= 36). A negative binomial regression model was used to determine the influence of these dietary practices on bone injury incidence. The model also included the following predictors: biological sex, athlete level, sport, whether they had a diagnosed condition that impacted bone or performance, years of dedicated training and weekly training volume. Bone injury incidence was 1.53-fold (p = 0.041, 95% CI: 1.02 – 2.31) greater in those who used fasted training than those who did not. Bone injury incidence was similar in those who used period(s) of reduced CHO intake than in those who did not. These data demonstrate that elite endurance athletes engage in periods of CHO restriction and fasted training, and that these practices can be associated with higher incidence of bone injuries. Future research should aim to determine the direct influence of both acute and chronic reductions in CHO availability and the potential impact this has on bone remodelling, bone injury and bone health.

After 10 Weeks of Endurance Training, A High Carbohydrate Diet With a Low Glycaemic Index Results in Similar Changes in Body Fat Mass Compared to a Ketogenic Diet

Moitzi A1, M Gleichweit1, A Feichter1, C Kamaryt1, D König1,2

1Department of Nutritional Sciences, University of Vienna, Austria

2Centre for Sports Science and University Sports, University of Vienna, Austria

It is well known that training and manipulation in macronutrient intake help reducing body weight and fat mass while increasing fat-free mass to reach an optimal balance between strength/power and body mass, which is desirable for endurance athletes. The hypothesis of the present investigation was that a high carbohydrate diet with a low glycaemic index would be able to achieve those adaptions by attenuating postprandial insulin secretion. After an initial exercise test, 57 recreational active male runners (age: 28 ± 5 y, peak oxygen uptake: 55.7 ± 7.7 mL/min/kg) were randomly assigned to one of three experimental groups (LOW-GI: ≥ 65% low glycaemic carbohydrates daily, n = 19; HIGH-GI: ≥ 65% high glycaemic carbohydrates daily, n = 19; LCHF: ≥ 65% fat, ≤ 50 g carbohydrates daily, n = 19) stratified by their VO2 peak. During ten weeks, participants completed five running sessions per week and fed according to the assigned nutritional regime. Body mass and composition was assessed before, during and after the intervention using bioelectrical impedance analysis (seca mBCA 515, Hamburg, Germany). To detect changes from pre- to post-intervention a one-way ANOVA followed by Tukey’s multiple comparisons test and to identify mean differences at the three timepoints, between groups and corresponding interactions a two-way mixed ANOVA was used. Significance was accepted at p< 0.05. Results are reported as mean±standard deviation. Respectively, there were changes to all three timepoints in weight, BMI, absolute and relative fat mass in LOW-GI and LCHF. Reductions in body weight and BMI were evenly lower in HIGH-GI (-1.7 ± 2.3 kg, -0.5 ± 0.7 kg*m-2, n=16) and similar in LCHF (-4.8 ± 3.2 kg, -1.4 ± 1.0 kg*m-2, n=17) and LOW-GI (-3.9 ± 3.4 kg, -1.3 ± 1.0 kg*m-2, n=16). Reductions in absolute fat mass were greater in LOW-GI (-3.9 ± 3.0 kg, p=0.026) and LCHF (-4.1 ± 2.6 kg, p=0.012) than HIGH-GI (-1.3 ± 2.6 kg). There were no differences in changes in fat-free or skeletal muscle mass, but there was a trend towards higher losses in fat free mass in LCHF than the carbohydrate diets. In terms of reducing fat mass and maintaining fat-free mass a LOW-GI diet is comparable to a LCHF diet. In contrast to the LCHF diet, the changes in LOW-GI were achieved with a supply of carbohydrates in line with the requirements for endurance sports. It could be speculated that this was due to the higher rate of fat oxidation in LOW-GI because of lower insulin levels compared to HIGH-GI.

Influence of Time-Of-Day That Acute Nitrate-Rich Beetroot Juice is Consumed on Blood Pressure and Exercise Tolerance

Rowland SN1, LJ James1, E O’Donnell1, SJ Bailey1

1Loughborough University, Loughborough, United Kingdom

Dietary nitrate (NO3-) supplementation can lower systolic blood pressure (SBP) and improve exercise performance, with such effects positively associated with plasma nitrite concentration ([NO2-]). Salivary flow rate (SFR) and pH have been reported to follow a circadian rhythm and to peak in the afternoon. An elevated SFR would be expected to increase NO3- secretion into the oral cavity and elevated salivary pH has been reported to enhance oral NO3- reduction to NO2-. This study tested the hypotheses that NO3--rich beetroot juice (BR) would increase plasma [NO2-], lower SBP and improve exercise tolerance to a greater extent in the afternoon compared to the morning and evening. Twelve healthy males completed six separate trials, BR and NO3--depleted beetroot juice (PL) ingested in the morning (BR-MORN and PL-MORN), afternoon (BR-AFT, PL-AFT) and evening (BR-EVE and PL-EVE) in a repeated-measures, crossover design. Following baseline measurements of SFR, salivary pH, plasma [NO2-], and brachial and central SBP, with the latter determined via applanation tonometry, participants ingested 140 mL of concentrated BR (13 mmol NO3-) or PL. Measurements were repeated 2.5 h after ingestion and a severe-intensity time to exhaustion (TTE) cycling test was subsequently completed. There were no differences between the BR trials in mean SFR or salivary pH (P>0.05). Plasma [NO2-] was not different after BR ingestion between BR-MORN (642 ± 289 nM), BR-AFT (670 ± 314 nM) and BR-EVE (675 ± 355 nM; all P>0.05). Compared to baseline, brachial SBP at 2.5 h was lowered in BR-MORN (4 ± 7 mmHg, P<0.05), but unchanged in BR-AFT and BR-EVE (P> 0.05). Central SBP was reduced in BR-MORN (3 ± 4 mmHg), BR-AFT (4 ± 3 mmHg), and BR-EVE (2 ± 3 mmHg, all P<0.05), with no differences between conditions (P> 0.05). Exercise TTE was not different between BR and PL at any timepoint (P> 0.05). Acute BR consumption resulted in comparable increases in plasma [NO2-] and reductions in central SBP in the morning, afternoon, and evening, but only lowered brachial SBP in the morning. There were no improvements in TTE following BR ingestion at any timepoint. These findings improve understanding of how the timing of BR ingestion might influence its effects on vascular function, but do not support acute BR ingestion to improve endurance performance.

Trimethylamine N-Oxide Concentrations and Blood Pressure in Females Across the Menstrual Cycle and Oral Contraceptive Pill Phases and Compared to Males

Rowland SN1, LM Heaney1, LJ James1, E O’Donnell1, SJ Bailey1

1Loughborough University, Loughborough, United Kingdom

Trimethylamine N-oxide (TMAO), a gut-derived metabolite and marker of gut dysbiosis, has been linked to hypertension and cardiovascular disease. Systolic blood pressure (SBP) is proposed to be elevated in females using hormonal contraceptives and males than in age-matched females with a natural menstrual cycle, but the extent to which [TMAO] differs between these populations has yet to be investigated. The purpose of this study was to assess whether plasma [TMAO] and SBP differed across the menstrual cycle (MC) and phase of oral contraceptive pill use in females, and in males versus females. Brachial and central SBP were measured, with the latter determined via applanation tonometry, and plasma [TMAO] was assessed using liquid chromatography-mass spectrometry in: naturally menstruating females (NMF) (n = 11) during the early follicular phase (EFP) and mid-luteal phase (MLP); in combined, monophasic oral contraceptive pill using females (OCP) (n = 9) during days 1-4 of the pill free interval (inactive) and days 17-21 of pill consumption (active), and in males (n = 9). There were no differences in [TMAO], or brachial or central SBP between NMF averaged across the MC (1.9 ± 1.0 uM, 106 ± 8 mmHg, 94 ± 9 mmHg) and OCP averaged across both pill phases (2.0 ± 1.5 uM, 108 ± 5 mmHg, 94 ± 4 mmHg, P>0.05), or between EFP and MLP (P>0.05), or inactive and active pill phases (P>0.05). Brachial SBP was higher in men (118 ± 4 mmHg) than NMF and OCP across all phases (P<0.05). Central SBP was higher in men (98 ± 3 mmHg) than OCP in both phases (P<0.05), but not different to NMF (P>0.05). [TMAO] was higher in men (3.3 ± 1.5 uM) than NMF in the MLP (1.8 ± 0.8 uM, P<0.05), and OCP in the active phase (1.7 ± 1.0 uM, P<0.05), but not different to NMF in the EFP or OCP in the inactive phase (P>0.05). There was a positive correlation between [TMAO] and brachial SBP averaged across the MC in NMF (P<0.05, r=0.611), but no correlations between [TMAO] and brachial SBP in OCP averaged across both pill phases or males (P>0.05), or between [TMAO] and central SBP (P>0.05). Plasma [TMAO] was not different across the MC or contraceptive pill phase, or between NMF and OCP. However, males exhibited higher SBP and plasma [TMAO] than age-matched NMF and OCP. These findings improve understanding of the link between plasma [TMAO] and SBP in healthy adults.

Effects of Internal Cooling on Physical Performance, Physiological and Perceptional Parameters When Exercising in the Heat: A Systematic Review With Meta-Analyses

Heydenreich J1,2, K Koehler1,3, H Braun1,4, M Grosshauser1,5, H Heseker1,6, D Koenig1,7, A Lampen1,8, S Mosler1,9, A Niess1,10, A Schek1,11, R Ziegenhagen1,12, A Carlsohn1,13

1Working Group Sports Nutrition of German Nutrition Society

2Institute of Sports Sciences, Johannes Gutenberg University Mainz, Germany

3Department of Sport & Health Sciences, Technical University of Munich, Germany

4Manfred Donike Institute for Doping Analysis, Institute of Biochemistry, German Sport University Cologne, Germany

5Olympic Center Rhineland-Palatinate/Saarland, Germany

6Institute of Nutrition, Consumption and Health, University of Paderborn, Germany

7Division of Sports Medicine, Exercise Physiology and Prevention, Center for Sport Science and University Sports, University of Vienna, Austria

8Food Safety Department, German Federal Institute for Risk Assessment, Germany

9Institute of Health Sciences, University of Education Schwäbisch Gmünd, Germany

10Department of Sports Medicine, University Hospital Tübingen, Germany

11Editorial team Leistungssport, German Olympic Sports Confederation, Germany

12Food Safety Department, German Federal Institute for Risk Assessment, Germany

13Department of Nutrition and Home Economics, University of Applied Science Hamburg, Germany

An elevated core temperature (Tcore) increases the risk of performance impairments and heat-related illness. Internal cooling (IC) has the potential to lower Tcore when exercising in the heat. The aim of the review was to systematically analyze the effects of IC on performance, physiological, and perceptional parameters. A systematic literature search was performed in the PubMed database on 17 December, 2021. Intervention studies were included assessing the effects of IC on performance, physiological, or perceptional outcomes. Data extraction and quality assessment were conducted for the included literature. The standardized mean differences (SMD) and 95% Confidence Intervals (CI) were calculated using the inverse-variance method and a random-effects model. 45 studies involving 465 active subjects (13.5% female; mean age 20 – 42 years) were included in the meta-analysis. IC resulted in positive effects on time to exhaustion (SMD [95% CI] 0.40 [0.13; 0.67], p < 0.01) and mean power output (0.26 [0.03; 0.48], p < 0.05). IC reduced Tcore (-0.21 [-0.37; -0.06], p < 0.01), sweat rate (-0.22 [-0.36; -0.08], p < 0.01), and thermal sensation (-0.18 [-0.34; -0.01], p < 0.05). IC resulted in a borderline reduction in time trial performance (0.31 [-0.60; -0.02], p = 0.06), heart rate (-0.13 [-0.27; 0.01], p = 0.06), and rate of perceived exertion (-0.16 [-0.31; -0.00], p = 0.05), whereas no effects were found for skin temperature, blood lactate, and thermal comfort (all p > 0.05). IC has the potential to support endurance performance and selected physiological and perceptional parameters. Future research should confirm the laboratory-based results in the field setting and involve non-endurance activities and female athletes. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022336623

Prevalence of Dietary Supplement Consumption in Swiss Endurance-Trained and Moderately Active Subjects

Czech F1, R Frank1, J Heydenreich1,2

1Institute of Sports Sciences, Johannes Gutenberg University Mainz, Mainz, Germany

2Swiss Federal Institute of Sport Magglingen SFISM, Magglingen, Switzerland

Dietary supplement (DS) use is widely spread among athletes in various sports to enhance performance, reduce the risk of injury, stay healthy, and optimize regeneration. The purpose of the present study was to investigate the prevalence of DS use and to check for possible sex differences. In 125 endurance-trained and moderately active participants (49% female, 28 ± 6 yr, 22 ± 2 kg/m2, Physical Activity Level 1.9 ± 0.3), the DS intake was assessed using a standardized dietary record on seven consecutive days. DS intake was categorized using the ABCD classification system of the Australian Institute of Sports (AIS). Fisher’s exact test was utilized to identify sex-based differences in the prevalence of DS use (α=0.05). The prevalence of DS use was 62% (women 66%, men 59%). DS of group A had with 53% the highest prevalence (women 54%, men 51%), caused by a high intake of sports food (total 49%, women 49%, men 48%) and medical supplements (total 19 %, women 16%, men 20%). The DS with the highest prevalence was isolated protein with 24% (women 23%, men 25%) followed by sports drinks (total 17%, women 16%, men 17%) and multivitamins (total 14%, women 12%, men 17%). There were neither sex differences in the overall prevalence of DS use nor for any group or subgroup level or single DS (all p > 0.05). The present study confirms the results of previous studies showing a relatively high prevalence of DS use in athletes. The motives and the need for the use of DS remain unclear among participants of the present study. However, athletes should carefully weigh out risks (e.g., contamination, exceeding upper limits) and benefits (e.g., meeting dietary recommendations) of DS use before supplementation and should be assisted by a (sports-) nutrition expert or medical doctor.

Total Energy Expenditure in Japanese College Male Sprinters Using the Double Labeled Water Method

Shimamura Y1, R Takemura1, K Iwanami1, D Yamamoto1, H Sagayama2, K Iwayama1

1Graduate School of Physical Education Studies Graduate Program in Physical Education, Tenri University, Japan

2Graduate School of Comprehensive Human Sciences, University of Tsukuba, Japan

Anaerobic power output is associated with whole-body muscle mass and directly affects sprint performance. It is necessary to know that the optimal energy intake for increasing and maintaining muscle mass. Effectively making ideal body composition, total energy expenditure (TEE) should be identified, and intake adequate energy in the daily diet. Some previous studies have investigated TEE in a variety of athletes, but few studies were reported on sprinters during the training season. The purpose of this study was to determine the TEE and physical activity level (PAL) of sprinters using the doubly labeled water (DLW) method, which is the gold standard for assessing energy expenditure under free living. Five Japanese college male sprinters (age: 21 ± 1y, height: 170.9 ± 0.4cm, body mass: 61.4 ± 5.5kg, body fat percentage: 9.5 ± 0.8%) participated in this study. The best record for that season were 10.84 ± 0.16 s (100m, n=3), 49.23 s (400m, n=1), and 53.70 s (400mH, n=1). They are classified as sub-elite sprinters according to a participant classification framework on previous studies. The TEE was evaluated over 7 days during training season, and the athletes engaged in their training for 5-6 days·week-1, 174 ± 41 minutes·day-1. Body mass and body composition did not change between pre- and post-measurement using a bioelectrical impedance. The PAL was calculated from TEE/measured resting energy expenditure. The EI was estimated from the Food Frequency Questionnaire. The average TEE, PAL, and EI were 13.1 ± 1.1 MJ·day-1 (3132 ± 234 kcal·day-1), 1.88 ± 0.17 and 12.5 ± 3.1 MJ·day-1 (2979 ± 740 kcal·day-1), respectively. There was no difference between the TEE and EI, and the EI was comparable to Dietary Reference Intakes for Japanese. These results indicated that Japanese college male sprinters, the equivalent of sub-elite, may maintain energy-balanced conditions during the training season. Therefore, it is considered that male college sprinters can use the recommended dietary requirements in order to achieve optimal body mass and composition. This is the first study that TEE in sprinters during training season has been assessed using the DLW method, and the results may be useful in establishing energy requirements for other athletes.

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