Work Volume and Strength Training Responses to Resistive Exercise Improve with Periodic Heat Extraction from the Palm
Grahn, Dennis A; Cao, Vinh H; Nguyen, Christopher M; Liu, Mengyuan T; Heller, H Craig
Body core cooling via the palm of a hand increases work volume during resistive exercise. We asked: 1) is there a correlation between elevated core temperatures and fatigue onset during resistive exercise, and 2) does palm cooling between sets of resistive exercise affect strength and work volume training responses? Core temperature was manipulated by 30-45 min of fixed load and duration treadmill exercise in the heat with or without palm cooling. Work volume was then assessed by 4 sets of fixed load bench press exercises. Core temperatures were reduced and work volumes increased following palm cooling (Control: Tes=39.0+/-0.1[degrees]C, 36+/-7 reps vs. Cooling: Tes=38.4+/-0.2[degrees]C, 42+/-7 reps, mean+/-SD, n=8, p<0.001). In separate experiments the impact of palm cooling on work volume and strength training responses were assessed. Participants completed bi-weekly bench press or pull-up exercises for multiple successive weeks. Palm cooling was applied for 3 minutes between sets of exercise. Over three weeks of bench press training, palm cooling increased work volume by 40% (vs.13% with no treatment) (n=8, p<0.05). Over six weeks of pull-up training, palm cooling increased work volume by 144% in pull-up experienced subjects (vs. 5% over 2 weeks with no treatment) (n=7, p<0.001) and by 80% in pull-up naive subjects (vs. 20% with no treatment) (n=11, p<0.01). Strength (1-RM) increased 22% over 10 weeks of pyramid bench press training (4 weeks with no treatment followed by 6 weeks with palm cooling) (n=10, p<0.001). These results verify previous observations about the effects of palm cooling on work volume, demonstrate a link between core temperature and fatigue onset during resistive exercise, and suggest a novel means for improving strength and work volume training responses.