The effects of acute heat exposure on muscular strength, muscular endurance, and power in the euhdrated athlete
Hedley, A, Climstein, M & Hanson, R 2002, 'The effects of acute heat exposure on muscular strength, muscular endurance, and power in the euhdrated athlete', Journal of Strength and Conditioning Research, vol. 16, no. 3, pp. 353-358.
The purpose of this study was to determine the effects of acute heat exposure upon muscularstrength, muscular endurance, and muscular power in euhydrated athletes. Ten healthy, weight-trained men (average age = 23.0 ± 4.0 years) volunteered for this investigation. Subjects were randomized to normothermic (22.5° C, 65% relative humidity [RH]) or hyperthermic (65–75° C, 15% RH) condition for 30 minutes. Results indicated that all subjects experienced significant (p < 0.05) hemodynamic stress because of the 30 minutes ofheat exposure (blood pressure [BP]rest 124/78 mm Hg to BPpostsauna 148/60 mm Hg, heart rate [HR]rest 64 b-min-1 to HRpostsauna 122 b·min-1). Oral and tympanic temperature measurements correlated strongly (r2 = 0.904) and increased by 2.48 and 2.71° C, respectively, during sauna exposure. One repetition maximum (1RM) bench press strength did not differ between the 2 conditions, whereas 1RM leg press strength was significantly decreased (p < 0.05) after the hyperthermic protocol. Subjects' muscular endurance decreased significantly (p < 0.05) in both the leg press (29.2%) and bench press (15.8%) after the sauna exposure. In contrast, muscularpower (vertical jump) increased significantly (3.1%, p < 0.5) after acute heat exposure. In agreement with previous studies, we concluded that acute heat exposure is detrimental to muscular endurance; however, the areas ofstrength and power are far less unequivocal.