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Annemiek J. Roete, Marije T. Elferink-Gemser, Ruby T.A. Otter, Inge K. Stoter, and Robert P. Lamberts

Purpose: The aim of this brief review was to present an overview of noninvasive markers in trained to professional endurance athletes that can reflect a state of functional overreaching. Methods: A systematic literature search was conducted in the PubMed, Scopus, and PsycINFO databases. After screening 380 articles, 12 research papers were included for the systematic review. Results: Good consensus was found between the different papers in which noninvasive parameters were able to reflect a state of functional overreaching. Changes in power output (PO), heart rate (HR; [sub]maximal and HR recovery), rating of perceived exertion, and scores in the Daily Analysis of Life Demands for Athletes (DALDA) and/or Profile of Mood States (POMS) were shown to be able to reflect functional overreaching, whereas changes in maximal oxygen uptake and HR-variability parameters were not. Conclusion: Functional overreaching within a maximal performance test was characterized by a decrease in peak PO and a lower maximum HR, whereas a lower mean PO and a lower HR were observed during time trials. Changes in parameters during a standardized submaximal test when functionally overreached were characterized by a higher PO at a fixed HR or a lower HR at a fixed intensity, higher rating of perceived exertion, and a faster HR recovery. Although both the DALDA and POMS were able to reflect functional overreaching, the POMS was not able to differentiate this response from acute fatigue, which makes it unsuitable for accurately monitoring functional overreaching.

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Wesley O’Brien, Tara Coppinger, Irene Hogan, Sarahjane Belton, Marie H. Murphy, Cormac Powell, and Catherine Woods

Background: The current study was the largest physical activity (PA) surveillance assessment of youth undertaken in Ireland in recent years. The purpose of this research was to assess the impact of social support, while controlling for age and screen time, on PA and sport participation, across a representative sample of Irish female youth. Methods: A total of 3503 children (mean age: 13.54 [2.05] y) across the island of Ireland participated. Participants completed a previously validated electronic questionnaire while supervised in a classroom setting, which investigated their (1) levels of PA; (2) screen time; (3) community sport participation; and (4) social support (friend, family, and teacher) to be physically active/partake in sport. Results: There were significant differences, with medium and large effect sizes, for social support from friends and family across types of sports participation. Specifically, girls who participated in the most popular team sports, when compared with the most popular individual sports, reported higher social support scores for friends and family structures. Conclusions: Findings from this study confirm the contributing influence of friends and family as sport and PA support networks for girls. Interventions should consider the importance of culturally relevant team sports for PA engagement in female youth.

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Michelle T. Barrack, Marta D. Van Loan, Mitchell Rauh, and Jeanne F. Nichols

This prospective study evaluated the 3-year change in menstrual function and bone mass among 40 female adolescent endurance runners (age 15.9 ± 1.0 years) according to baseline disordered eating status. Three years after initial data collection, runners underwent follow-up measures including the Eating Disorder Examination Questionnaire and a survey evaluating menstrual function, running training, injury history, and prior sports participation. Dual-energy X-ray absorptiometry was used to measure bone mineral density and body composition. Runners with a weight concern, shape concern, or global score ≥4.0 or reporting >1 pathologic behavior in the past 28 days were classified with disordered eating. Compared with runners with normal Eating Disorder Examination Questionnaire scores at baseline, runners with disordered eating at baseline reported fewer menstrual cycles/year (6.4 ± 4.5 vs. 10.5 ± 2.8, p = .005), more years of amenorrhea (1.6 ± 1.4 vs. 0.3 ± 0.5, p = .03), and a higher proportion of menstrual irregularity (75.0% vs. 31.3%, p = .02) and failed to increase lumbar spine or total hip bone mineral density at the 3-year follow-up. In a multivariate model including body mass index and menstrual cycles in the past year at baseline, baseline shape concern score (B = −0.57, p value = .001) was inversely related to the annual number of menstrual cycles between assessments. Weight concern score (B = −0.40, p value = .005) was inversely associated with lumbar spine bone mineral density Z-score change between assessments according to a multivariate model adjusting for age and body mass index. These finding support associations between disordered eating at baseline and future menstrual irregularities or reduced accrual of lumbar spine bone mass in female adolescent endurance runners.

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Brianne A. Bruijns, Leigh M. Vanderloo, Brian W. Timmons, and Patricia Tucker

Background: Moderate-to-vigorous physical activity (MVPA) offers many health benefits for preschoolers (2.5–5 y). In childcare, MVPA is predominantly accumulated outdoors, with higher rates purported among children within the first few minutes outside. The Supporting Physical Activity in the Childcare Environment intervention included shorter, more frequent outdoor play sessions; this study sought to explore children’s activity levels during various outdoor play schedules. Methods: During the final week of the Supporting Physical Activity in the Childcare Environment intervention, preschoolers wore an Actical accelerometer for 5 days during childcare and staff logged outdoor times. Separate linear mixed effects models were run to explore the effect of the intervention on preschoolers’ physical activity (total and MVPA) and sedentary time during outdoor play. Sex was entered as an interaction effect. Results: Preschoolers (n = 292) were significantly more active in the first 10 minutes outdoors compared with remaining time (P < .0083). For total outdoor time, children in the experimental group engaged in significantly less sedentary time than those in the control group (P < .017), and experimental group boys and girls engaged in higher MVPA than boys and girls in the control group (P < .017). Conclusions: Findings support scheduling more frequent outdoor play sessions in childcare to increase physical activity participation among young children.

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Takuya Ibara, Makoto Takahashi, Koichi Shinkoda, Mahito Kawashima, and Masaya Anan

This study aimed to investigate the hip sway and the relationship between the center of pressure (CoP) and kinematic parameters regarding the time series scaling component α in patients with hip osteoarthritis (OA) during a one-leg standing task. The scaling exponent α, SD, hip sway maximal acceleration change, and balance performance, which was measured using CoP parameters, were compared between hip OA and control groups during a one-leg standing task. The relationships between balance performance with CoP parameters and kinematic parameters were investigated with the regression analysis. In the hip OA group, the scaling exponent α was smaller in the medial–lateral direction, and the SD and maximal amount of change in hip sway acceleration were larger in the anterior–posterior direction in the hip OA group. In this group, the CoP parameters were significantly associated with α in the medial–lateral direction (negatively) and in the anterior–posterior direction (positively). In the hip OA group, hip sway adaptability in the medial–lateral direction was limited, while the anterior–posterior direction showed greater movement.

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Gabriel Perri Esteves, Paul Swinton, Craig Sale, Ruth M. James, Guilherme Giannini Artioli, Hamilton Roschel, Bruno Gualano, Bryan Saunders, and Eimear Dolan

Currently, little is known about the extent of interindividual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high-intensity cycling capacity test (CCT110%) were meta-analyzed. Changes in time to exhaustion (TTE) and muscle carnosine were the primary and secondary outcomes. Multilevel distributional Bayesian models were used to estimate the mean and SD of BA and placebo group change scores. The relative sizes of group SDs were used to infer whether observed variation in change scores were due to intervention or non-intervention-related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7, 95% credible interval [CrI] [1.3, 14.3] s) and muscle carnosine (18.1, 95% CrI [14.5, 21.9] mmol/kg DM). A large intervention response variation was identified for muscle carnosine (σIR = 5.8, 95% CrI [4.2, 7.4] mmol/kg DM) while equivalent change score SDs were shown for TTE in both the placebo (16.1, 95% CrI [13.0, 21.3] s) and BA (15.9, 95% CrI [13.0, 20.0] s) conditions, with the probability that SD was greater in placebo being 0.64. In conclusion, the similarity in observed change score SDs between groups for TTE indicates the source of variation is common to both groups, and therefore unrelated to the supplement itself, likely originating instead from external factors such as nutritional intake, sleep patterns, or training status.

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Elliott C.R. Hall, Sandro S. Almeida, Shane M. Heffernan, Sarah J. Lockey, Adam J. Herbert, Peter Callus, Stephen H. Day, Charles R. Pedlar, Courtney Kipps, Malcolm Collins, Yannis P. Pitsiladis, Mark A. Bennett, Liam P. Kilduff, Georgina K. Stebbings, Robert M. Erskine, and Alun G. Williams

Purpose: Genetic polymorphisms have been associated with the adaptation to training in maximal oxygen uptake (V˙O2max). However, the genotype distribution of selected polymorphisms in athletic cohorts is unknown, with their influence on performance characteristics also undetermined. This study investigated whether the genotype distributions of 3 polymorphisms previously associated with V˙O2max training adaptation are associated with elite athlete status and performance characteristics in runners and rugby athletes, competitors for whom aerobic metabolism is important. Methods: Genomic DNA was collected from 732 men including 165 long-distance runners, 212 elite rugby union athletes, and 355 nonathletes. Genotype and allele frequencies of PRDM1 rs10499043 C/T, GRIN3A rs1535628 G/A, and KCNH8 rs4973706 T/C were compared between athletes and nonathletes. Personal-best marathon times in runners, as well as in-game performance variables and playing position, of rugby athletes were analyzed according to genotype. Results: Runners with PRDM1 T alleles recorded marathon times ∼3 minutes faster than CC homozygotes (02:27:55 [00:07:32] h vs 02:31:03 [00:08:24] h, P = .023). Rugby athletes had 1.57 times greater odds of possessing the KCNH8 TT genotype than nonathletes (65.5% vs 54.7%, χ 2 = 6.494, P = .013). No other associations were identified. Conclusions: This study is the first to demonstrate that polymorphisms previously associated with V˙O2max training adaptations in nonathletes are also associated with marathon performance (PRDM1) and elite rugby union status (KCNH8). The genotypes and alleles previously associated with superior endurance-training adaptation appear to be advantageous in long-distance running and achieving elite status in rugby union.

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Alexandru Nicolae Ungureanu, Corrado Lupo, Gennaro Boccia, and Paolo Riccardo Brustio

Purpose: The primary aim of this study was to evaluate whether the internal (session rating of perceived exertion [sRPE] and Edwards heart-rate-based method) and external training load (jumps) affect the presession well-being perception on the day after (ie, +22 h), according to age and tactical position, in elite (ie, Serie A2) female volleyball training. Methods: Ten female elite volleyball players (age = 23 [4] y, height = 1.82 [0.04] m, body mass = 73.2 [4.9] kg) had their heart rate monitored during 13 team (115 individual) training sessions (duration: 101 [8] min). Mixed-effect models were applied to evaluate whether sRPE, Edwards method, and jumps were correlated (P ≤ .05) to Hooper index factors (ie, perceived sleep quality/disorders, stress level, fatigue, and delayed-onset muscle soreness) in relation to age and tactical position (ie, hitters, central blockers, opposites, and setters). Results: The results showed a direct relationship between sRPE (P < .001) and presession well-being perception 22 hours apart, whereas the relationship was the inverse for Edwards method internal training load. Age, as well as the performed jumps, did not affect the well-being perception of the day after. Finally, central blockers experienced a higher delayed-onset muscle soreness than hitters (P = .003). Conclusions: Findings indicated that female volleyball players’ internal training load influences the pretraining well-being status on the day after (+ 22 h). Therefore, coaches can benefit from this information to accurately implement periodization in a short-term perspective and to properly adopt recovery strategies in relation to the players’ well-being status.

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Christian J. Cook, Blair T. Crewther, Liam P. Kilduff, Linda L. Agnew, Phillip Fourie, and Benjamin G. Serpell

Purpose: To establish if training volume was associated with androgen baselines and androgen responsiveness to acute exercise. Methods: During a “high-volume” training phase, 28 cyclists (14 men and 14 women) undertook oxygen-uptake and maximal-work-capacity testing. Two days later, they completed a repeat-sprint protocol, which was repeated 3 weeks later during a “low-volume” phase. Blood and saliva samples were collected before and after (+5 and +60 min) the repeat-sprint protocol. Blood was assayed for total testosterone (TT), free testosterone (FT), and dihydrotestosterone (DHT) and saliva, for testosterone and DHT. Results: Pretrial TT, FT, and DHT concentration was greater for males (P < .001, large effect size differences), and in both genders TT, DHT, and saliva for DHT was higher during high-volume loading (moderate to large effect size). Area-under-the-curve analysis revealed larger TT, FT, and DHT responses to the repeat-sprint protocol among females, and high-volume training was linked to larger TT, DHT, and saliva for DHT responses (moderate to large effect size). Baseline TT and FT correlated with oxygen uptake and work capacity in both genders (P < .05). Conclusion: DHT showed no acute performance correlation but was responsive to volume of training, particularly in females. This work informs on timelines and relationships of androgenic biomarkers in males and females across different training loads, adding to the complexity that should be considered in interpretation thereof. The authors speculate that testosterone may impact acute performance via behavioral mechanisms of motivation and attention; DHT, via training volume-induced androgenic promotion, may facilitate long-term adaptive changes, especially for females.

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Ciaran O’Grady, Louis Passfield, and James G. Hopker

Purpose: Rating of perceived exertion (RPE) as a training-intensity prescription has been extensively used by athletes and coaches. However, individual variability in the physiological response to exercise prescribed using RPE has not been investigated. Methods: Twenty well-trained competitive cyclists (male = 18, female = 2, maximum oxygen consumption =55.07 [11.06] mL·kg−1·min−1) completed 3 exercise trials each consisting of 9 randomized self-paced exercise bouts of either 1, 4, or 8 minutes at RPEs of 9, 13, and 17. Within-athlete variability (WAV) and between-athletes variability (BAV) in power and physiological responses were calculated using the coefficient of variation. Total variability was calculated as the ratio of WAV to BAV. Results: Increased RPEs were associated with higher power, heart rate, work, volume of expired oxygen (VO2), volume of expired carbon dioxide (VCO2), minute ventilation (V E), deoxyhemoglobin (ΔHHb) (P < .001), and lower tissue saturation index (ΔTSI%) and ΔO2Hb (oxyhaemoglobin; P < .001). At an RPE of 9, shorter durations resulted in lower VO2 (P < .05) and decreased ΔTSI%, and the ΔHHb increased as the duration increased (P < .05). At an RPE of 13, shorter durations resulted in lower VO2, V E, and percentage of maximum oxygen consumption (P < .001), as well as higher power, heart rate, ΔHHb (P < .001), and ΔTSI% (P < .05). At an RPE of 17, power (P < .001) and ΔTSI% (P < .05) increased as duration decreased. As intensity and duration increased, WAV and BAV in power, work, heart rate, VO2, VCO2, and VE decreased, and WAV and BAV in near-infrared spectroscopy increased. Conclusions: Self-paced intensity prescriptions of high effort and long duration result in the greatest consistency on both a within- and between-athletes basis.