Effects of Whole Body Heating During Warm-up on Strength, Power, and Flexibility

Background/Hypothesis: There has been little research investigating the use of external heat to enhance muscular performance. The purpose of this study is to compare the differences between warming up in a hot (H) and neutral (N) temperature environment on muscle performance. Methods: Seven (M:3/F:4) Division I collegiate athletes (age = 20 ± 1; weight = 78.8 ± 24.7 kg; height = 176.2 ± 7.6 cm; body fat 19.7 ± 11.3%) each completed 2-trials in a randomized, counter-balanced order. Subjects warmed up in a temperature and humidity controlled chamber at 20 °C (N) and 40 °C (H), both at 40% humidity, on differing days separated by 1-week. Following the warm-up in both conditions, flexibility (FLEX) was assessed using a sit and reach test, maximal strength (MS) using 1-repetition maximum for back squat (BS) and bench press (BP), and peak power (PP) using serial weight attempts for the power clean. All movement parameters were recorded using a bar accelerometer and analyzed using a paired t-test. Results: No differences were found between N and H for FLEX (49.98 vs. 44.54 cm, p = 0.17); PP: (1974.3 vs. 2114.6 W, p = 0.63); MS: (BS: 152.3 vs. 147.7 kg, p = 0.65) and (BP: 65.9 vs. 66.5 kg, p = 0.68). Eccentric force during BP difference was greater in H (N: 806.7 vs. H: 899.7 N; p = 0.01). Conclusion: Based on our findings, there appears to be no practical performance advantage of warming up in an H environment compared to a N environment