ABSTRACT: Local cooling can induce an ergogenic effect during a short-term intense exercise. One proposed method of personal cooling involves heat extraction from the palm.
Purpose: In this study, we hypothesized that local palm cooling (PC) during rest intervals between progressive weight training sets will increase total repetitions and exercise volume in resistance-trained subjects exercising in a thermoneutral (TN) environment.
Methods: Sixteen male subjects (mean ± SD; age = 26 ± 6 yr, height = 178 ± 7 cm, body mass = 81.5 ± 11.3 kg, one-repetition maximum (1RM) bench press = 123.5 ± 12.6 kg, weight training experience = 10 ± 6 yr) performed four sets of 85% 1RM bench press exercise to fatigue, with 3-min rest intervals. Exercise trials were performed in a counterbalanced order for 3 d, separated by at least 3 d: TN, palm heating (PH), and PC. Heating and cooling were applied by placing the hand in a device called the rapid thermal exchanger, set to 45°C for heating or 10°C for cooling. This device heats or cools the palm while negative pressure (−35 to −45 mm Hg) is applied around the hand.
Results: Total exercise volume during the four PC sets (2480 ± 636 kg) was significantly higher than that during TN (1972 ± 632 kg) and PH sets (2156 ± 668 kg, P < 0.01). The RMS of the surface EMG with PC exercise was higher (P < 0.01), whereas esophageal temperature (P < 0.05) and RPE (P < 0.05) were lower during PC compared with TN and PH.
Conclusions: PC from 35°C to 20°C temporarily overrides fatigue mechanism(s) during intense intermittent resistance exercise. The mechanisms for this ergogenic function remain unknown.