Effects of Whole Body Heating During Warm-up on Strength, Power, and Flexibility Trevor Krzyzanowski, Caleb Ross, Daniel Newmire, Dustin Slivka University of Nebraska at Omaha, School of Health, Physical Education, and Recreation, Omaha, NE Exercise Physiology Lab ABSTRACT METHODS RESULTS 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 & 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. 7 NCAA Division I athletes (3: ♂, 4: ♀) participated in this study (Table 1) and completed 3 visits. Visit #1 consisted of: Informed consent, and descriptive data Visit #2 and #3: Subjects completed the standardized 20 min warm-up protocol in differing environmental temperatures of at 40 °C and 20 °C (A). Following the warm-up, the subjects completed: Three Sit & Reach Test trials were conducted to test for flexibility. The Bar Sensei™ (B, C) was used to assess peak power during the Power Clean Test and maximal strength for both the Bench Press Test and Back Squat Test. A B INTRODUCTION Figure 1-5: All data expressed in Mean  SEM. Neutral (N) and Heat (H) for FLEX (N: 49.98  3.4 vs. H: 44.54  2.4 cm, p = 0.17); PP: (N: 1974  261.4 vs. H: 2115  347.2 W, p = 0.63); MS for BS (N: 152.3  7.91 vs. 147.7  5.8 kg, p = 0.65) and MS for BP (N: 65.9  8.36 vs. H: 66.5  8.44 kg, p = 0.68). (* p = < 0.05), eccentric force during BP difference found greater in H (N: 806.7  132.1 vs. H: 899.7  141 N; p = 0.01). A warm-up is a commonly used method to prepare the body and mind for muscular performance. Flexibility has been shown to improve following a warm-up routine. Muscular performance increases in high-heat and humidity conditions in female soccer player’s 40-yard dash times. In-vitro muscle contraction performance is shown to increase in the heat * C METHODS CONCLUSIONS Intramuscular temperatures may have not been high enough to elicit a meaningful change. Greater eccentric force was observed during the Bench Press Test after the warm-up in 40 °C environment. Overall, a warm-up in 40 °C did not show a greater advantage on muscle performance measures of power and strength using human model. Funding was provided by the University of Nebraska-Omaha Office of Research and Creative Activity FUSE Grant Sit & Reach (Flexibility) Power Clean (Peak Power) Back Squat (Lower Body Muscular Strength) Bench Press (Upper Body Muscular Strength)