Heated Resistance Training Does Not Impact Deadlift Or Bench Press Bar Velocity In Females

Muscular performance responses to low volume-load resistance training (RT) may be acutely enhanced in the heat but there is a lack of data describing responses to high volume-load RT in the heat. PURPOSE: To determine if bar velocity of deadlift (DL) or bench press (BP) is affected by high volume-load, whole-body RT in a hot (HOT; 40 ± 1 °C, 39 ± 5 % [RH]) versus temperate environment (TEMP; 20 ± 2 °C, 39 ± 5 % RH). METHODS: Eight resistance-trained females completed RT in HOT and TEMP in a randomized crossover fashion. The RT protocol was 4 sets of 10 repetitions at 70% one-repetition maximum (1RM) with 2-3 min rest between sets of DL, BP, bent over row, split squat, shoulder press, and biceps curls. Muscular performance was assessed before and after RT using a load-velocity protocol. Participants lifted 40, 60, 80, and 90% of DL and BP 1RM for 2-3 repetitions while recording peak barbell velocity. Muscle temperature was estimated via skin temperature pre- and post-RT at the vastus lateralis (TVL) and triceps brachii (TTB). Effects and interactions of condition (HOT vs TEMP) and time (Pre- vs Post-RT) were assessed using separate two-way repeated measures ANOVAs. RESULTS: A two-way interaction was observed for 40% 1RM of BP (p < 0.01, ηp2 = 0.76) such that in HOT velocity was not different (Pre; 1.26 ± 0.22 m·s-1, Post; 1.23 ± 0.12 m·s-1, p = 0.43) but in TEMP, velocity increased from pre- (0.88 ± 0.13 m·s-1) to Post-RT (1.17 ± 0.18 m·s-1, p < 0.01). In all DL loads, velocity decreased from pre- to post-RT regardless of environment (p ≤ 0.05, ηp2 ≥ 0.44). TVL had a two-way interaction (p = 0.01, ηp2 = 0.63) such that in HOT, TVL was not different Pre-RT (37.83 ± 0.53 °C) to Post-RT (37.84 ± 0.42 °C, p = 0.85) while in TEMP, TVL decreased from Pre-RT (35.24 ± 0.42 °C) to Post-RT (34.83 ± 0.45 °C, p < 0.01). Both TVL and TTB were affected by condition (p < 0.01, ηp2 ≥ 0.87) with higher temperatures in HOT at both time points (TTB: Pre-RT HOT; 37.83 ± 0.28 °C, Post-RT HOT; 38.02 ± 0.17 °C, Pre-RT TEMP; 34.68 ± 1.67 °C, Post-RT TEMP; 35.13 ± 1.03 °C). CONCLUSION: In females, high volume-load RT can be performed in a hot environment without significant bar velocity decrements. The views expressed in this abstract are those of the authors and do not reflect the official policy of the U.S. Government, Department of Energy, Department of the Army, or Department of Defense.