Purpose: To determine the effect of wearing a phase-change cooling vest in elite female rugby sevens athletes during (1) a simulated match-day warm-up in hot conditions prior to a training session and (2) a prematch warm-up during a tournament in cool conditions. Methods: This study consisted of 2 randomized independent group designs (separated by 16 d) where athletes completed the same 23- to 25-minute match-day warm-up (1) in hot conditions (range = 28.0°C to 35.1°C wet bulb globe temperature [WBGT]) prior to training and (2) in cool conditions (range = 18.8°C to 20.1°C WBGT) prior to a World Rugby Women’s Sevens Series match. In both conditions, athletes were randomly assigned to wearing either (1) the standardized training/playing ensemble (synthetic rugby shorts and training tee/jersey) or (2) the standardized training/playing ensemble plus a commercial phase-change athletic cooling vest. Group-wise differences in core temperature rise from baseline, global positioning system–measured external locomotive output, and perceptual thermal load were compared. Results: Core temperature rise during a match warm-up was lower in the hot condition only (−0.65°C [95% confidence interval = −1.22°C to −0.08°C],
Henderson, Fransen, Coutts, and Taylor are with the Faculty of Health, School of Sport, Exercise and Rehabilitation and the Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, NSW, Australia. Henderson is also with Australian Rugby Sevens, Rugby Australia (RA), Sydney, NSW, Australia. Chrismas is with the Sport Science Program, College of Arts and Science, Qatar University, Doha, Qatar. Stevens is with the School of Health and Human Sciences, Southern Cross University, Coffs Harbour, NSW, Australia. Taylor is also with the School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom, and Qatar Orthopedic and Sports Medicine Hospital, Athlete Health and Performance Research Center, ASPETAR, Doha, Qatar.