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Beatriz Rael, Nuria Romero-Parra, Víctor M. Alfaro-Magallanes, Laura Barba-Moreno, Rocío Cupeiro, Xanne Janse de Jonge, Ana B. Peinado and on Behalf of the IronFEMME Study Group

Purpose: The influence of female sex hormones on body fluid regulation and metabolism homeostasis has been widely studied. However, it remains unclear whether hormone fluctuations throughout the menstrual cycle (MC) and with oral contraceptive (OC) use affect body composition (BC). Thus, the aim of this study was to investigate BC over the MC and OC cycle in well-trained females. Methods: A total of 52 eumenorrheic and 33 monophasic OC-taking well-trained females participated in this study. Several BC variables were measured through bioelectrical impedance analysis 3 times in the eumenorrheic group (early follicular phase, late follicular phase, and midluteal phase) and on 2 occasions in the OC group (withdrawal phase and active pill phase). Results: Mixed linear model tests reported no significant differences in the BC variables (body weight, body mass index, basal metabolism, fat mass, fat-free mass, and total body water) between the MC phases or between the OC phases (P > .05 for all comparisons). Trivial and small effect sizes were found for all BC variables when comparing the MC phases in eumenorrheic females, as well as for the OC cycle phases. Conclusions: According to the results, sex hormone fluctuations throughout the menstrual and OC cycle do not influence BC variables measured by bioelectrical impedance in well-trained females. Therefore, it seems that bioimpedance analysis can be conducted at any moment of the cycle, both for eumenorrheic women and women using OC.

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Courtney Sullivan, Thomas Kempton, Patrick Ward and Aaron J. Coutts

Purpose: To develop position-specific career performance trajectories and determine the age of peak performance of professional Australian Football players. Methods: Match performance data (Australian Football League [AFL] Player Rank) were collected for Australian Football players drafted via the AFL National Draft between 1999 and 2015 (N = 207). Players were subdivided into playing positions: forwards (n = 60; age 23 [3] y), defenders (n = 71; age 24 [4] y), midfielders (n = 58; age 24 [4] y), and ruckmen (n = 18; age 24 [3] y). Linear mixed models were fitted to the data to estimate individual career trajectories. Results: Forwards, midfielders, and defenders experienced peak match performance earlier than ruckmen (24–25 vs 27 y). Midfielders demonstrated the greatest between-subjects variability (intercept 0.580, age 0.0286) in comparison with ruckmen, who demonstrated the least variability (intercept 0.112, age 0.005) in AFL Player Rank throughout their careers. Age had the greatest influence on the career trajectory of midfielders (β [SE] = 0.226 [0.025], T = 9.10, P < .01) and the least effect on ruckmen (β [SE] = 0.114 [0.049], T = 2.30, P = .02). Conclusions: Professional Australian Football players peak in match performance between 24 and 27 years of age with age, having the greatest influence on the match performance of midfielders and the least on ruckmen.

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Tom Toolis and Kerry McGawley

Purpose: To evaluate the effects of wearing upper- and lower-body compression garments on cross-country skiing performance in elite winter biathletes. Methods: A total of 7 senior biathletes (4 men and 3 women) from the Swedish national team performed 2 exercise trials in a randomized and counterbalanced order, wearing either commercially available upper- and lower-body compression garments (COMP) or a standard winter-biathlon racing suit (CON). In each trial, the athletes roller-skied on a customized treadmill, completing a time trial simulating the skiing duration of a biathlon sprint race, followed by a time-to-exhaustion test designed to elicit exhaustion within ∼60 to 90 seconds. Heart rate, blood lactate concentration, rating of perceived exertion, thermal sensation, and thermal comfort were monitored throughout each trial, while muscle soreness was measured up to 48 hours after each trial. Results: Pressure exerted by the clothing was significantly higher at all anatomical sites for COMP compared with CON (P ≤ .002). Wearing COMP led to small positive effects on time-trial (d = 0.31) and time-to-exhaustion test (d = 0.31) performances compared with CON, but these differences were not statistically significant (P > .05). No significant differences were found for any physiological (heart rate or blood lactate concentration) or subjective (rating of perceived exertion, thermal sensation, thermal comfort, or muscle soreness) responses between COMP and CON (P > .05). Conclusion: Wearing COMP during maximal cross-country skiing may have small but worthwhile beneficial effects on performance for some individuals. Due to individual variation, athletes are advised to test COMP prior to competition.

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Fernando Pareja-Blanco, Eduardo Sáez de Villarreal, Beatriz Bachero-Mena, Ricardo Mora-Custodio, José Antonio Asián-Clemente, Irineu Loturco and David Rodríguez-Rosell

Purpose: This study aimed to compare the effects of unresisted versus heavy sled sprint training (0% vs 40% body mass [BM]) on sprint performance in women. Moreover, the effects of the aforementioned loads on resisted sprint and jump performance were analyzed. Methods: Twenty-eight physically active women were randomly allocated into 2 groups: unloaded sprint training group (G0%, n = 14), and resisted sprint training with 40% BM group (G40%, n = 14). Pretraining and posttraining assessments included countermovement jump, unloaded 30-m sprint, and 20-m sprint with 20%, 40%, 60%, and 80% BM. Times to cover 0 to 10 (T10), 0 to 20 (T20), 0 to 30 (T30), 10 to 20 (T10–20), 20 to 30 (T20–30), and 10 to 30 m (T10–30) were recorded. Both groups were trained once a week for 8 weeks and completed the same training program, but with different loads (0% vs 40% BM). Results: No significant time × group interactions were observed. For unloaded sprint performance, G0% showed significant (P = .027) decreases only in T10–20, while G40% attained significant decreases in T30 (P = .021), T10–30 (P = .015), and T20–30 (P = .003). Regarding resisted sprint performance, G0% showed significant (P = .010) improvements only for the 20% BM condition. The G40% group attained significant improvements in all loading conditions (20%, 40%, 60%, and 80% BM). Both groups showed significant improvements (P < .001) in countermovement jump height. Conclusions: In physically active women, no significant differences in sprint and countermovement jump performance were detected after 8 weeks of resisted and unresisted sprint training programs. Future studies should, therefore, be devoted to how sprint training should be individualized to maximize performance.

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Steven H. Doeven, Michel S. Brink, Barbara C.H. Huijgen, Johan de Jong and Koen A.P.M. Lemmink

In elite basketball, players are exposed to intensified competition periods when participating in both national and international competitions. How coaches manage training between matches and in reference to match scheduling for a full season is not yet known. Purpose: First, to compare load during short-term match congestion (ie, ≥2-match weeks) with regular competition (ie, 1-match weeks) in elite male professional basketball players. Second, to determine changes in well-being, recovery, neuromuscular performance, and injuries and illnesses between short-term match congestion and regular competition. Methods: Sixteen basketball players (age 24.8 [2.0] y, height 195.8 [7.5] cm, weight 94.8 [14.0] kg, body fat 11.9% [5.0%], VO2max 51.9 [5.3] mL·kg−1·min−1) were monitored during a full season. Session rating of perceived exertion (s-RPE) was obtained, and load was calculated (s-RPE × duration) for each training session or match. Perceived well-being (fatigue, sleep quality, general muscle soreness, stress levels, and mood) and total quality of recovery were assessed each training day. Countermovement jump height was measured, and a list of injuries and illnesses was collected weekly using the adapted Oslo Sports Trauma Research Center Questionnaire on Health Problems. Results: Total load (training sessions and matches; P < .001) and training load (P < .001) were significantly lower for ≥2-match weeks. Significantly higher well-being (P = .01) and less fatigue (P = .001) were found during ≥2-match weeks compared with 1-match weeks. Conclusion: Total load and training load were lower during short-term match congestion compared with regular competition. Furthermore, better well-being and less fatigue were demonstrated within short-term match congestion. This might indicate that coaches tend to overcompensate training load in intensified competition.

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Martin Buchheit, Ben M. Simpson and Mathieu Lacome

Purpose: To compare between-tests changes in submaximal exercise heart rate (HRex, 3 min, 12 km/h) and the speed associated with 4 mmol/L of blood lactate (V4mmol) in soccer players to get insight into their level of agreement and respective sensitivity to changes in players’ fitness. Methods: A total of 19 elite professional players (23 [3] y) performed 2 to 3 graded incremental treadmill tests (3-min stages interspersed with 1 min of passive recovery, starting speed 8 km/h, increment 2 km/h until exhaustion or 18 km/h if exhaustion was not reached before) over 1.5 seasons. The correlation between the changes in HRex and V4mmol was examined. Individual changes in the 2 variables were compared (>2 × typical error considered “clear”). Results: The changes in HRex and V4mmol were largely correlated (r = .82; 90% confidence interval, .65–.91). In more than 90% of the cases, when a clear individual change in HRex was observed, it was associated with a similar clear change in V4mmol (the same direction, improvement, or impairment of fitness) and conversely. Conclusions: When it comes to testing players submaximally, the present results suggest that practitioners can use HRex or V4mmol interchangeably with confidence. However, in comparison with a field-based standardized warm-up run (3–4 min, all players together), the value of a multistage incremental test with repeated blood lactate samplings is questionable for a monitoring purpose given its time, labor, cost, and poorer player buy-in.

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Jac Orie, Nico Hofman, Laurentius A. Meerhoff and Arno Knobbe

At the Olympic level, optimally distributing training intensity is crucial for maximizing performance. Purpose: The authors evaluated the effect of training-intensity distribution on anaerobic power as a substitute for 1500-m speed-skating performance in the 4 y leading up to an Olympic gold medal. Methods: During the preparation phase of the speed-skating season, anaerobic power was recorded periodically (n = 15) using the mean power (in watts) with a 30-s Wingate test. For each training session in the 4 wk prior to each Wingate test, the volume (in hours), training type (specific, simulation, nonspecific, and strength training), and the rating of perceived exertion (RPE; CR-10) were recorded. Results: Compared with the 8 lowest, the 7 highest-scoring tests were preceded by a significantly (P < .01) higher volume of strength training. Furthermore, the RPE distribution of the number of nonspecific training sessions was significantly different (P < .01). Significant (P < .05) correlations highlighted that a larger nonspecific training volume in the lower intensities RPE 2 (r = .735) and 3 (r = .592) was associated positively and the medium intensities RPE 4 (r = −.750) and 5 (r = −.579) negatively with Wingate performance. Conclusion: For the subject, the best results were attained with a high volume of strength training and the bulk of nonspecific training at RPE 2 and 3, and specifically not at the adjoining RPE 4 and 5. These findings are surprising given the aerobic nature of training at RPE 2 and 3 and the importance of anaerobic capacity in this middle-distance event.

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Fabio Bertapelli, Stamatis Agiovlasitis, Robert W. Motl, Roberto A. Soares, Marcos M. de Barros-Filho, Wilson D. do Amaral-Junior and Gil Guerra-Junior

The purpose of this study was to develop and cross-validate an equation for estimating percentage body fat (%BF) from body mass index and other potential independent variables among young persons with intellectual disability. Participants were 128 persons with intellectual disability (62 women; age 16–24 years) split between development (n = 98) and cross-validation (n = 30) samples. Dual-energy X-ray absorptiometry served as the reference method for %BF. An equation including 1/body mass index and sex (0 = male; 1 = female) was highly accurate in estimating %BF (p < .001; R 2 = .82; standard error of estimate  = 5.22%). Mean absolute and root mean square errors were small (3.1% and 3.9%, respectively). A Bland–Altman plot indicated nearly zero mean difference between actual and predicted %BF with modest 95% confidence intervals. The prediction equation was %BF = 56.708 − (729.200 × [1/body mass index]) + (12.134 × sex). Health care professionals may use the prediction equation for monitoring %BF among young people with intellectual disability.