Physiologic Responses to Heavy-Resistance Exercise with Very Short Rest Periods*

Abstract

Heavy-resistance exercise utilizing very short rest periods is commonly used by body builders to prepare for competition. The purpose of this study was to compare the acute responses of this type of heavy-resistance exercise protocol in competitive body builders (BB) and power lifters (PL). Nine male BB and eight PL were matched for age, size and experience. A ten-station heavy-resistance exercise protocol was used. Each subject performed three sets of 10 repetition maximum (RM) with 10-s rest between sets and alternated 30-s and 60-s rest periods between exercises. No differences were observed in total work between the groups, but BB used a significantly (PPr = 0.84). Plasma epinephrine, norepinephrine, dopamine, cortisol, and lactate levels significantly increased from pre- to 5 min post-exercise. Mean plasma volumes were reduced -16.6 (±3.64)% and -20.6 (±8.32)% following the exercise protocol for BB and PL, respectively. Significant (P<0.05) decreases in eosinophil counts were observed following exercise. No significant differences were observed between BB and PL for any of the physiologic responses measured. PL exhibited a higher incidence (100%) of clinical symptoms of dizziness and nausea compared to BB (11.1%). These data suggest that exercise protocols used by BB results in a similar stress response in both types of competitive lifters. Still, BB appear to better tolerate this type of exercise protocol based on enhanced exercise performance and reduced sympatomatology. This may be due to different chronic adaptations associated with the respective styles of training used by these two groups of athletes.