Purpose: To determine the effects of low-dose caffeine supplementation (3 mg/kg body mass) consumed 1 h before the experiment on rating of perceived exertion (RPE), skills performance (SP), and physicality in male college ice hockey players. Methods: Using a double-blind, placebo-controlled, randomized crossover experimental design, 15 college ice hockey players participated in SP trials and 14 participated in scrimmage (SC) trials on a total of 4 d, with prescribed ice hockey tasks occurring after a 1-h high-intensity practice. In the SP trials, time to complete and error rate for each drill of the validated Western Hockey League Combines Testing Standard were recorded. Peak head accelerations, trunk contacts, and offensive performance were quantified during the SC trials using accelerometery and video analysis. RPE was assessed in both the SP and SC trials. Results: RPE was significantly greater in the caffeine (11.3 [2.0]) than placebo (9.9 [1.9]) condition postpractice (P = .002), with a trend toward greater RPE in caffeine (16.9 [1.8]) than placebo (15.7 [2.8]) post-SC (P = .05). There was a greater number of peak head accelerations in the caffeine (4.35 [0.24]) than placebo (4.14 [0.24]) condition (P = .028). Performance times, error rate, and RPE were not different between intervention conditions during the SP trials (P > .05). Conclusions: A low dose of caffeine has limited impact on sport-specific skill performance and RPE but may enhance physicality during ice hockey SCs.
Robyn F. Madden, Kelly A. Erdman, Jane Shearer, Lawrence L. Spriet, Reed Ferber, Ash T. Kolstad, Jessica L. Bigg, Alexander S.D. Gamble, and Lauren C. Benson
DIGEST VOLUME 6, ISSUE #1
); and (ii) analyse the mediation effect of accelerometery-based physical activity (PA) on associations. The study was conducted in Spain with 415 children (9.1 ;± 0.4 years) and 853 adolescents (13.6 ± 1.6 years). Total accelerometer-based ST was positively associated with global adiposity in children
Shaun J. McLaren, Jonathan M. Taylor, Tom W. Macpherson, Iain R. Spears, and Matthew Weston
velocity and accelerometery data using bespoke algorithms (methods not publicly available). Signal quality was visually inspected after each session, and we found no instances of inaccuracies. As the RST program required players to run the same distance at the same intensity for each sprint, traditional
Oliver J. Chrzanowski-Smith, Robert M. Edinburgh, Mark P. Thomas, Aaron Hengist, Sean Williams, James A. Betts, and Javier T. Gonzalez
activity energy expenditure (kcal·day −1 ). Habitual levels of physical activity energy expenditure were assessed by a chest-worn physical activity monitor (Actiheart ™ ; Cambridge Neurotechnology, Papworth, United Kingdom) that combines accelerometery and heart rate. Participants wore the monitor over the