Chris McLellan

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

Objectives To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass. Design A repeated measure, prospective, observational, cohort study. Setting Griffith University, Gold Coast, Australia. Participants 37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2. Primary and secondary outcome measures Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season. Results Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm2; mid=1.296(0.093) g/cm2; p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury. Conclusions Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.

The hormonal response of older men to sub-maximum aerobic exercise: The effect of training and detraining

The hormonal response of 32 older men (70-80years) to a bout of sub-maximum aerobic exercise was examined before, after 16weeks of resistance or aerobic training and again after 4weeks of detraining. Blood samples were obtained at rest and immediately post sub-maximum exercise (30min @ 70% VO(2) max) to determine the concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone (Test), sex hormone-binding globulin (SHBG) and the calculation of free testosterone (FT). Both training groups had significant increases in leg strength and VO(2) max after 16weeks training but leg strength and VO(2) max returned to pre-training levels in the aerobic training and resistance training groups, respectively. During the 20week study there was no change in resting concentrations of any hormones among the three groups. There was no increase in GH, IGF-1 or SHBG immediately post sub-maximum exercise in any of the groups before training, after 16weeks training or after 4weeks detraining. Testosterone and FT increased immediately post sub-maximum exercise within all groups before training, after 16weeks training and after 4weeks detraining with the increase in Test and FT higher after 16weeks of resistance training compared to before training and after 4weeks detraining within the resistance training group. The increased responsiveness of Test and FT after 16weeks of resistance training was lost after 4weeks of detraining. Our results indicate that some physiological and hormonal adaptations gained after 16weeks training are lost after only 4weeks detraining.

The contribution of energy systems during the upper body Wingate anaerobic test.

The purpose of this study was to measure the contribution of the aerobic, anaerobic lactic, and alactic systems during an upper body Wingate Anaerobic test (WAnT). Oxygen uptake and blood lactate were measured before, during, and after the WAnT and body composition analyzed by dual-energy X-ray absorptiometry. The contribution of the energy systems was 11.4% ± 1.4%, 60.3% ± 5.6%, and 28.3% ± 4.9% for the aerobic, anaerobic lactic, and alactic systems, respectively.

The Use of Performance Tests for the Physiological Monitoring of Training in Combat Sports: A Case Study of a World Ranked Mixed Martial Arts Fighter

Currently there is little data on the changes in physiological performance of combat athletes in response to changes in training during fight preparation. Therefore the aim of this study was to examine the use of the 30-s Wingate test as a means of monitoring an athlete’s performance during their fight preparation. A world ranked mixed martial arts fighter volunteered to participate in the eight week study. Upper and lower body anaerobic performance was assessed at baseline and three and six weeks into the preparation phase with the final assessment two weeks after the tapering period. Upper and lower body maximal oxygen uptake (VO2 max) was measured before and after the eight weeks of fight preparation. Increases in training load were matched by substantial decreases in upper and lower body anaerobic performance during first three and six weeks of the preparation phase. During the tapering period anaerobic performance substantially increased in both the upper and lower body. The upper and lower body VO2 max (14% and 3% respectively) substantially increased after the eight week preparation phase with upper body peak power (10.5%) and maximum heart (4%) higher. Our data suggest that Wingate performance is able to track changes in training loads and can assist in the monitoring of performance of high-intensity combat athletes.

Performance and Metabolic Responses of Highly-Trained Team-Sport Athletes during Repeated Sprinting in Hypoxia

To examine the performance (i.e., peak and mean speed) and metabolic responses (i.e., O2 uptake and blood lactate concentration) of highly-trained team-sport athletes during repeated sprinting in hypoxia. Seven professional Australian-rules football players (i.e., AFL players; age, 20 ± 1 yr; stature, 190 ± 6 cm; body mass, 86.4 ± 9.8 kg) participated in this study. AFL players were required to complete ten, 6-s sprints with 24 s recovery (i.e., repeated-sprint running test; RSR test) on a non-motorised treadmill in normobaric normoxia, FiO2: 20.9% (RSN) and in normobaric hypoxia, FiO2: 14.0% (RSH). Peak and mean speed were determined, and oxygen uptake, blood lactate concentration and arterial oxygen saturation were obtained to examine metabolism.

Technical and Physical Performance over an English Championship League Season

The English Championship League (ECL) has a demanding ten-month schedule possibly exposing players to residual fatigue if they play the majority of matches. When present, residual fatigue may be evidenced by reduced physical and technical match performances as the season advances. The aim of this study was to investigate if differences in physical and technical performance occurred across a season for 11 ECL footballers who played the majority of matches that season. From the home matches analysed, only total distance covered was different (p = 0.0258), where it peaked at mid-season compared to two months later (p = 0.0104). Team possession remained stable throughout the season. Relative total distance covered by the team when in possession was 72 m/min less (p < 0.0001) than out of possession. In summary, maintaining possession during matches may reduce physical demands imposed on players and help preserve performance throughout the season.

The effect of previous wingate performance using one body region on subsequent wingate performance using a different body region

Abstract The 30 second Wingate Anaerobic Test (WAnT) is the gold standard measure of anaerobic performance. The present investigation aimed to determine if a previous WAnT using one body region significantly affected a subsequent WAnT using a different body region. Twelve male university students (n = 12, 23 ± 2 years, 84 ± 16.1 kg, 178.5 ± 7.4 cm) volunteered to complete two repeated WAnT protocols (either lower body WAnT followed by an upper body WAnT or vice versa) on two separate testing occasions. The upper body WAnT was conducted on a modified electromagnetically braked cycle ergometer using a flywheel braking force corresponding to 5% bodyweight. The lower body WAnT was conducted on an electronically braked cycle ergometer using a flywheel braking force corresponding to 7.5% bodyweight. Participants had a 1 minute rest period for transition between WAnTs. Data are reported as mean ± standard deviation. No significant differences were identified in power indices for the lower body between 30 s WAnTs. When the upper body WAnT was performed 2nd, absolute peak power (p < 0.01), mean power (p < 0.001) and relative mean power (p < 0.001) were significantly lower compared to when the upper body WAnT was performed 1st. The value of maximum revolutions per minute was significantly lower (p < 0.001) when the upper body WAnT was performed after the lower body WAnT, compared to when it was performed 1st (193.3 ± 11.4 1st vs 179.8 ± 14.4 2nd). Previous upper body sprint exercise does not significantly affect lower body sprint exercise; however, previous lower body sprint exercise severely compromises subsequent upper body sprint performance.

A comparison of physical and technical match performance of a team competing in the English championship league and then the English premier league following promotion

The changes in match demands when a team is promoted from the English Championship League (ECL) to the English Premier League (EPL) remain unknown. To date, estimates of between-league differences are made using different teams. This study explores differences in physical and technical performance of players who competed in the ECL and then the EPL following promotion. Although total distance covered over the season was the only measure to significantly differ (p= 0.0001) between the ECL and EPL, the 3% increase in total distance in the EPL was deemed practically non-significant. In the EPL, players had an extra 57 ± 6 hours (p = 0.0002) between matches, yet this had little affect on total, sprint and high intensity distances. In summary, higher league standard may not require greater physical capacity and developing a tactical strategy to suit the ability of players that is sustainable across leagues is important.

Gender Differences in Upper and Lower Body Performance during High Intensity Intermittent Exercise

Objective: To compare upper and lower body 5x6s performance between males and females to determine if significant gender differences exist. Methods: Twenty physically active adults (males n=12, females n=8) volunteered to perform an upper and lower body 5x6s. The upper body 5x6s was conducted on a modified electro-magnetically braked cycle ergometer, while the lower body 5x6s was conducted on an electronically braked cycle ergometer using a flywheel braking force corresponding to 5% and 7.5% bodyweight respectively. During the upper body 5x6s, participants were restrained at the waist with an adjustable seatbelt in an attempt to minimise the contribution from the lower body. Body composition was assessed using dual-energy X-ray absorptiometry (DEXA). Data are reported as means ± standard deviation (SD). A level of significance of 5% (P<0.05) was adopted in all analyses. Results: Significant (p<0.001) differences occurred in both absolute (W) and relative (W·kg-1) PP and mean power (MP) between genders during the upper body 5x6s, with differences remaining even when relative to lean body mass (LBM) and active muscle mass (AMM). In contrast, PP and MP for the lower body 5x6s was only significantly different between genders when expressed in absolute (W) and relative (W·kg-1) terms. Conclusion: While both lower body 5x6s performance and lower body 5x6s predictors do not differ significantly between genders, significant differences do exist for upper body 5x6s performance and performance predictors. Even after allometric scaling and training status have been considered, significant gender differences still remain for upper body 5x6s performance, suggesting that unknown intrinsic muscle properties may be responsible for the significant gender differences observed. Thus, females must be trained differently to their male counterparts during upper body exercise.