Combined Carbohydrate and Protein Ingestion During Australian Rules Football Matches and Training Sessions Does Not Reduce Fatigue or Accelerate Recovery Throughout a Weeklong Junior Tournament.

Lee, NA, Fell, JW, Pitchford, NW, Hall, AH, Leveritt, MD, and Kitic, CM. Combined carbohydrate and protein ingestion during Australian rules football matches and training sessions does not reduce fatigue or accelerate recovery throughout a weeklong junior tournament. J Strength Cond Res 32(2): 344-355, 2018-Australian rules football (ARF) is a physically demanding sport that can induce high levels of fatigue. Fatigue may be intensified during periods where multiple matches are played with limited recovery time. Combined carbohydrate and protein (CHO + PRO) intake during physical activity may provide performance and recovery benefits. The aim of this study was to investigate whether CHO + PRO ingestion during ARF matches and training sessions throughout a tournament would enhance performance or recovery in comparison with CHO-only ingestion. Australian rules football players (n = 21) competing in a 7-day national tournament participated in this randomized and double-blinded study. Beverages containing either CHO (n = 10) or CHO + PRO (n = 11) were provided during matches (day 1, day 4, and day 7) and training sessions (day 2 and day 3). Countermovement jumps (CMJs), ratings of muscle soreness, and autonomic function were assessed throughout the tournament. Gastrointestinal tract (GI) discomfort was measured after matches. Countermovement jump peak velocity increased in the CHO + PRO group (p = 0.01) but not in the CHO group. There were no differences in the other CMJ variables. In both groups, muscle soreness increased from days 0 and 1 to day 2 (p ≤ 0.05) but did not remain elevated. R-R intervals (time elapsed between successive peaks in QRS complexes) increased in both groups from day 1 to day 7 (mean difference = 59.85 ms, p < 0.01). Postmatch GI discomfort was not different (p > 0.05) between groups. When daily dietary protein is adequate (>1.8 g·kg·d), the ingestion of CHO + PRO during matches and training sessions throughout a tournament does not reduce muscle soreness nor have clear benefits for neuromuscular recovery or modulate autonomic function in junior ARF athletes, compared with that of CHO alone.

Coingestion of carbohydrate and protein during training reduces training stress and enhances subsequent exercise performance.

Researchers have focused primarily on investigating the effects of coingesting carbohydrate (CHO) and protein (PRO) during recovery and, as such, there is limited research investigating the benefits of CHO+PRO coingestion during exercise for enhancing subsequent exercise performance. The aim of this study was to investigate whether coingestion of CHO+PRO during endurance training would enhance recovery and subsequent exercise performance. Ten well-trained male cyclists (aged 29.7 ± 7.5 years; maximal oxygen uptake, 66.2 ± 6 mL·kg(-1)·min(-1)) took part in a randomized, double-blind, cross-over trial. Each trial consisted of a 2.5-h morning training bout during which the cyclists ingested a CHO+PRO or energy-matched CHO beverage followed by a 4-h recovery period and a subsequent performance time trial (total work, 7 kJ·kg(-1)). Blood was collected before and after exercise. Time-trial performance was 1.8% faster in the CHO+PRO trial compared with the CHO trial (p = 0.149; 95% CI, -13 to 87 s; 75.8% likelihood of benefit). The increase in myoglobin level from before the training bout to after the training bout was lower in the CHO+PRO trial (0.74 nmol·L(-1); 95% CI, 0.3-1.17 nmol·L(-1)) compared with the CHO trial (1.16 nmol·L(-1); 95% CI, 0.6-1.71 nmol·L(-1)) (p = 0.018). Additionally, the decrease in neutrophil count over the recovery period was greater in the CHO+PRO trial (p = 0.034), and heart rate (p < 0.022) and rating of perceived exertion (RPE) (p < 0.01) were lower during training in the CHO+PRO trial compared with the CHO trial. Ingesting PRO, in addition to CHO, during strenuous training lowered exercise stress, as indicated by reduced heart rate, RPE, and muscle damage, when compared with CHO alone. CHO+PRO ingestion during training is also likely to enhance recovery, providing a worthwhile improvement in subsequent cycling time-trial performance.

Exposure levels and determinants of softwood dust exposures in BC lumber mills, 1981-1997.

Measurements of personal exposure to wood dust (n = 1237) collected by the Workers' Compensation Board of British Columbia, Canada, over the period 1981-1997 were used to construct an empirical model to identify broad determinants of softwood dust exposure. Potential determinants of exposure examined included species of tree processed; company; geographic location of lumber mill; department; job title; calendar year; and production factors such as board feet of lumber produced per year. A determinants of exposure model was built using multiple linear regression. Nested within this compliance database was a subset of samples collected for a research study. These enabled the authors to explore whether differences in exposure measurements can in part be explained by sampling strategy (research versus compliance). Potential differences were examined by examining differences in means for each job title, stratified by sampling strategy; and by offering "sampling strategy" as a categorical predictor variable to the empirical model. Multiple linear regressions revealed the most important determinants of increased wood dust exposure to be mill location away from the coast, earlier calendar year, and indoor jobs. The empirical model had an R2 of 0.39 and a predictive range from 0.02 to 25.45 mg/m3. Research and compliance sampling strategies showed no difference in mean exposure and distribution in the empirical model (p < 0.05), suggesting that regulatory exposure databases may be of utility for exposure assessment in epidemiology. This research indicates that compliance-sampling strategies do not result in an overestimation of mean exposure levels within jobs, but they do focus on a biased sample of jobs-those most highly exposed.