Rugby is a worldwide intermittent team sport. Players tend to be heavier than the majority of similar team sport athletes on whom the dietary guidelines have been developed. Therefore, the aim of the current review was to describe the intakes of rugby union players. Article databases were searched up to February 2017 and were included if they were published in English and reported dietary intakes of male rugby union players. Of the research articles identified, energy intakes were lower than two of three studies that reported intakes and expenditure, which would suggest the players were losing weight that is somewhat supported by the decreases in skinfolds seen during preseason. However, it should also be noted that there are errors in both the measurement of energy intakes and expenditure. Carbohydrate intakes ranged from 2.6 to 6.5 g·kg−1·day−1, which is lower than the current relative to body mass recommendations; however, this would not be classed as a low-carbohydrate diet. The consistently low intakes of carbohydrate suggest that these intake levels maybe sufficient for performance, given the players greater body mass or there are errors in the measurements. However, there is currently no evidence for the carbohydrate needs of rugby union players in terms of performance. The lower intakes than expenditure would suggest the players were losing weight. Previous research shows that rugby union players lose body fat during preseason training.
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Macronutrient Intakes of Male Rugby Union Players: A Review
Katherine Elizabeth Black, Alistair David Black, and Dane Frances Baker
Multiday Pomegranate Extract Supplementation Decreases Oxygen Uptake During Submaximal Cycling Exercise, but Cosupplementation With N-acetylcysteine Negates the Effect
Emma M. Crum, Matthew J. Barnes, and Stephen R. Stannard
Pomegranate extract (POMx) has been suggested as an ergogenic aid due to its rich concentration of polyphenols, which are proposed to enhance nitric oxide bioavailability, thereby improving the efficiency of oxygen usage and, consequently, endurance exercise performance. Although acute POMx supplementation improves aerobic exercise performance in untrained individuals, trained athletes appear to require chronic supplementation for a similar effect. Furthermore, the combination of POMx with a thiol antioxidant may prove more effective than POMx alone, due to the protective effects of thiols on nitric oxide. Thus, this study hypothesized that multiday POMx supplementation would decrease the oxygen uptake (VO2) required by trained cyclists to perform submaximal exercise and increase performance during a time trial, and that thiol (N-acetylcysteine [NAC]) cosupplementation would enhance these effects. Eight cyclists completed four 8-day supplementation periods: POMx only, NAC only, POMx + NAC (BOTH), and placebo. Following supplementation, they performed submaximal cycling and a 5-min time trial, with VO2 and muscle oxygen saturation (SmO2) being recorded. A three-way (POMx × NAC × Intensity) repeated-measures analysis of variance with a Fisher’s least significant difference post hoc assessment was performed for dependent variables (p ≤ .05). VO2 during submaximal exercise was reduced with POMx versus placebo (−2.6 ml·min−1·kg−1, p = .009) and BOTH (−2.5 ml·min−1·kg−1, p < .05) and increased with NAC (+1.9 ml·min−1·kg−1, p < .03), despite no main effect of treatment on SmO2 or performance. It appears that POMx’s high polyphenol content reduced the VO2 required during submaximal exercise. However, NAC cosupplementation annulled this effect; thus, NAC may interact with nitric oxide to reduce its bioavailability.
No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise
Mark Messina, Heidi Lynch, Jared M. Dickinson, and Katharine E. Reed
Much attention has been given to determining the influence of total protein intake and protein source on gains in lean body mass (LBM) and strength in response to resistance exercise training (RET). Acute studies indicate that whey protein, likely related to its higher leucine content, stimulates muscle protein synthesis to a greater extent than proteins such as soy and casein. Less clear is the extent to which the type of protein supplemented impacts strength and LBM in long-term studies (≥6 weeks). Therefore, a meta-analysis was conducted to compare the effect of supplementation with soy protein to animal protein supplementation on strength and LBM in response to RET. Nine studies involving 266 participants suitable for inclusion in the meta-analysis were identified. Five studies compared whey with soy protein, and four studies compared soy protein with other proteins (beef, milk, or dairy protein). Meta-analysis showed that supplementing RET with whey or soy protein resulted in significant increases in strength but found no difference between groups (bench press: χ2 = 0.02, p = .90; squat: χ2 = 0.22, p = .64). There was no significant effect of whey or soy alone (n = 5) on LBM change and no differences between groups (χ2 = 0.00, p = .96). Strength and LBM both increased significantly in the “other protein” and the soy groups (n = 9), but there were no between-group differences (bench: χ2 = 0.02, p = .88; squat: χ2 = 0.78, p = .38; and LBM: χ2 = 0.06, p = .80). The results of this meta-analysis indicate that soy protein supplementation produces similar gains in strength and LBM in response to RET as whey protein.
The Precompetition Macronutrient Intake of Elite Gaelic Football Players
Cathal Cassidy, Kieran Collins, and Marcus Shortall
Competition-related dietary intake has not yet been investigated in Gaelic football. The present study examined the precompetition macronutrient intake of elite male Gaelic football players. Forty players from two teams completed a food diary on the 2 days preceding competition (Day 1 and Day 2) and on the match day prior to the match (match day). Carbohydrate intake was significantly greater on Day 2 compared with Day 1, for both absolute (295 ± 98 vs. 318 ± 77 g; p = .048; −23.6 g, 95% confidence interval [−47.3, 0.2]; Cohen’s d = 0.27) and relative intake (3.4 ± 1.1 vs. 3.7 ± 1.0 g/kg; p = .027; −0.3 g/kg, 95% confidence interval [−0.6, −0.03]; Cohen’s d = 0.32). The number of players in accordance with and not in accordance with the guidelines for carbohydrate intake on Day 2 was significantly different to an expected frequency distribution, χ2(1) = 32.400; p ≤ .001; φ = 0.9, with a greater number of players not meeting the guidelines (observed N = 2 vs. 38). The number of players in accordance with and not in accordance with the recommendations for carbohydrate intake on match day was significantly different to an expected frequency distribution, χ2(1) = 8.100; p = .004; φ = 0.45, with a greater number of players meeting the guidelines (observed N = 29 vs. 11). The major finding from the current investigation was that a significantly greater number of players did not meet carbohydrate intake guidelines on the day before competition. Individualized nutritional interventions are required in order to modify the current prematch dietary intake.
Protein Supplementation During a 6-Month Concurrent Training Program: Effect on Body Composition and Muscular Strength in Sedentary Individuals
Michael J. Ormsbee, Brandon D. Willingham, Tasha Marchant, Teresa L. Binkley, Bonny L. Specker, and Matthew D. Vukovich
We examined the effect of a protein supplement on muscular strength and body composition during 6 months of a 5 days/week concurrent strength and endurance training program. Sedentary males (n = 26) and females (n = 25), 18–25 years, were randomly assigned to receive a protein (PRO, 42 g/serving) or carbohydrate (CON) supplement twice daily. Strength and body composition (dual-energy X-ray absorptiometry) were assessed at baseline, 3 (3M), and 6 (6M) months. Protein intake was higher in PRO (PRO: 2.2 g/kg; CON: 1.1 g/kg; p < .001). Females in both groups gained similar strength at 3M and 6M in bench press and hip sled. Males in PRO gained more bench press strength at 3M (PRO: 24.6 ± 3.2 kg; CON: 14.3 ± 3.8 kg; p = .06) and 6M (PRO: 34.4 ± 4.3 kg; CON: 18.7 ± 5.1 kg; p = .03) and hip sled strength at 3M (PRO: 67.7 ± 9.2 kg; CON: 40.8 ± 10.8 kg, p = .07) and 6M (PRO: 94.0 ± 10.6 kg; CON: 65.1 ± 12.4 kg; p = .09) compared with CON. Females in PRO experienced a greater reduction in fat mass over the course of the study (6M) than CON (PRO: −1.7 ± 0.5 kg; CON: 0.1 ± 0.5 kg; p = .06). Changes in lean mass were similar for females in PRO and CON. Loss in fat mass was similar for males in PRO and CON at 3M and 6M. Males in PRO gained more lean mass at 3M compared with CON (PRO: 3.2 ± 0.3 kg; CON: 2.2 ± 0.4 kg; p = .1) but similar gains at 6M (PRO: 2.6 ± 0.4 kg; CON: 2.2 ± 0.5 kg; p = .6). The results of this study demonstrate that PRO used during a concurrent training program may augment positive changes in body composition in young sedentary males and females, and strength gains in males.
Whey Protein Augments Leucinemia and Postexercise p70S6K1 Activity Compared With a Hydrolyzed Collagen Blend When in Recovery From Training With Low Carbohydrate Availability
Samuel G. Impey, Kelly M. Hammond, Robert Naughton, Carl Langan-Evans, Sam O. Shepherd, Adam P. Sharples, Jessica Cegielski, Kenneth Smith, Stewart Jeromson, David L. Hamilton, Graeme L. Close, and James P. Morton
We examined the effects of whey versus collagen protein on skeletal muscle cell signaling responses associated with mitochondrial biogenesis and protein synthesis in recovery from an acute training session completed with low carbohydrate availability. In a repeated-measures design (after adhering to a 36-hr exercise–dietary intervention to standardize preexercise muscle glycogen), eight males completed a 75-min nonexhaustive cycling protocol and consumed 22 g of a hydrolyzed collagen blend (COLLAGEN) or whey (WHEY) protein 45 min prior to exercise, 22 g during exercise, and 22 g immediately postexercise. Exercise decreased (p < .05) muscle glycogen content by comparable levels from pre- to postexercise in both trials (≈300–150 mmol/kg·dry weight). WHEY protein induced greater increases in plasma branched chain amino acids (p = .03) and leucine (p = .02) than COLLAGEN. Exercise induced (p < .05) similar increases in PGC-1α (fivefold) mRNA at 1.5 hr postexercise between conditions, although no effect of exercise (p > .05) was observed for p53, Parkin, and Beclin1 mRNA. Exercise suppressed (p < .05) p70S6K1 activity in both conditions immediately postexercise (≈25 fmol·min−1·mg−1). Postexercise feeding increased p70S6K1 activity at 1.5 hr postexercise (p < .05), the magnitude of which was greater (p < .05) in WHEY (180 ± 105 fmol·min−1·mg−1) versus COLLAGEN (73 ± 42 fmol·min−1·mg−1). We conclude that protein composition does not modulate markers of mitochondrial biogenesis when in recovery from a training session deliberately completed with low carbohydrate availability. By contrast, whey protein augments postexercise p70S6K activity compared with hydrolyzed collagen, as likely mediated via increased leucine availability.
Awareness and Attitude Toward Use of Dietary Supplements and the Perceived Outcomes Among Saudi Adult Male Members of Fitness Centers in Saudi Arabia
Hanan A. Alfawaz, Soundararajan Krishnaswamy, Latifah Al-Faifi, Halima Ali Bin Atta, Mohammad Al-Shayaa, Saad A. Alghanim, and Nasser M. Al-Daghri
Dietary supplements are believed to enhance athletic performance and/or prevent/reverse pathological states. Despite the increasing use of dietary supplements in Saudi Arabia, systematic studies in this field are lacking. This study aims to assess the relation between demographic and social characteristics and dietary supplement use among adult males in Saudi Arabia. Demographic and dietary supplements data from fitness club participants were collected through a questionnaire, and the Pearson chi-square test was used to determine associations. A total of 448 apparently healthy adult males above 20 years of age, who were registered at fitness centers located in Saudi Arabia, participated in the study. The majority (275 [62%]) of the study participants were younger (20–30 years), of normal weight (189 [43%]), without health problems (332 [79%]), and obtained an undergraduate degree or higher (336 [77%]). The majority (58%) took supplements under the supervision of a professional and the rest depended on Internet (22%), friends (12%), or books (4%) for choosing supplement types. The main motives of the participants for visiting the fitness center were: weight loss (N = 149 [35%]), keeping fit (N = 101 [24%]), and muscle building (N = 151 [35%]). One hundred and fifty-five participants (44%) were taking supplements on a daily basis with 34 (10%) having taken it for a prolonged duration (>1 year). The most commonly used supplements were proteins (29%) and multivitamins (21%). Supplement use was not associated with the participants’ family income or level of education but was positively associated with younger age (<31 years), χ2(2, N = 443) = 4.96, p = .03.
Caffeine Consumption Is Associated With Higher Level of Physical Activity in Japanese Women
Julien Tripette, Haruka Murakami, Hidemi Hara, Ryoko Kawakami, Yuko Gando, Harumi Ohno, Nobuyuki Miyatake, and Motohiko Miyachi
Caffeine has been described as a sports performance-enhancing substance. However, it is unclear whether it can increase the level of physical activity (PA) in nonathletic individuals. This study investigates the relationship between daily caffeine consumption and (a) daily PA/fitness or (b) intervention-induced changes in PA in women and men. On the basis of responses to a dietary habit questionnaire, which included items on caffeinated beverages, 1,032 Japanese adults, were categorized into lower or higher caffeine consumption groups (relative to the median caffeine consumption). In each group, daily step count; sedentary time; and light, moderate, and vigorous PA outcomes were objectively measured. Physical fitness, including peak oxygen consumption, was also evaluated. The relationship between daily caffeine consumption and the change in the levels of PA was investigated in a subgroup of 202 subjects who participated in a 1-year PA counseling intervention. Women in the higher caffeine consumption group presented higher moderate-to-vigorous PA and step count compared with their counterparts in the lower consumption group (4.0 ± 2.1 vs. 3.3 ± 2.1 MET-hr/day, p < .001; 10,335 ± 3,499 vs. 9,375 ± 3,527 steps/day, p < .001). A significant positive correlation was noted between caffeine consumption and peak oxygen consumption among women (r = .15, p < .001). No caffeine-related effects were noted in men. The lower and higher caffeine consumption groups showed no significant differences in their levels of PA at the end of the 1-year intervention. Therefore, caffeine consumption appears to be associated with higher levels of PA in Japanese women. Further studies are needed to clarify this association.
Case Study: Physical Capacity and Nutritional Status Before and After a Single-Handed Yacht Race
Giovanna Ghiani, Sara Magnani, Azzurra Doneddu, Gianmarco Sainas, Virginia Pinna, Marco Caboi, Girolamo Palazzolo, Filippo Tocco, and Antonio Crisafulli
During solitary sailing, the sailor is exposed to sleep deprivation and difficulties in consuming regular meals. Sailor weight loss is often reported. In the present case study, we describe changes in the physical capacity and nutritional status of an athlete attempting a single-handed yacht race around the globe. An Italian male ocean racer (Gaetano Mura) asked for our help to reach an optimum level of physical and nutritional preparation. We planned his diet after assessing his anthropometric parameters and body composition, as well as his usual energy intake and nutritional expenditure. The diet consisted of 120 meals stored in sealed plastic bags. Before his departure, GM performed two incremental exercise tests (cycle ergometry and arm crank ergometry) to assess his physical capacity. Cardiac functions were also estimated by Doppler echocardiography. All measures and exercise tests were repeated 10 days after GM finished the race, which lasted 64 days. Anthropometric measures did not change significantly, with the exception of arm fat area and thigh muscle area, which decreased. There were evident increments in maximum oxygen intake and maximum workload during arm cranking after the race. On the contrary, maximum oxygen uptake and maximum workload decreased during cycling. Finally, end-diastolic and stroke volume decreased after the race. It was concluded that nutritional counseling was useful to avoid excessive changes in nutritional status and body composition due to 64 days of solitary navigation. However, a reduction in physical leg capacity and cardiovascular functions secondary to leg disuse were present.
Comparison of Bioelectrical Impedance Analysis and Dual-Energy X-Ray Absorptiometry for Estimating Bone Mineral Content
Tori M. Stone, Jonathan E. Wingo, Brett S. Nickerson, and Michael R. Esco
The purpose of this study was to validate single-frequency hand-to-foot bioelectrical impedance analysis (HFBIA) for estimating bone mineral content (BMC) using dual-energy X-ray absorptiometry as the criterion measure in healthy men and women aged 18–40 years. A total of 80 men and women participated in this study. BMC was estimated on the same day using HFBIA and dual-energy X-ray absorptiometry. The HFBIA device provided higher mean BMC values in men and the entire sample, but not in women. A smaller standard error of estimate was observed in women (0.20, corresponding to 8% of the mean reference BMC values) compared with men (0.39, corresponding to 12% of the mean reference BMC values) and the combined sample (0.31). HFBIA provided a smaller constant error and individual estimation error indicated by the 95% limits of agreement in women (−0.05 ± 0.39) compared with men (−0.16 ± 0.78) and the entire sample (−0.10 ± 0.63). In conclusion, although BMC values were found to be more accurate in women, HFBIA overestimated BMC compared with dual-energy X-ray absorptiometry, especially in individuals with lower values. Given these results, using HFBIA to measure BMC would be inappropriate for diagnostic purposes.