Resumen de The effect of Between-Set Rest Intervals on the Oxygen Uptake During and After Resistance Exercise Sessions Performed with Large- and Small-Muscle Mass
Paulo de Tarso Veras Farinatti, Antonio Gil Castinheiras Neto
Between-set rest intervals (RIs) may influence accumulated fatigue, work volume, and therefore oxygen uptake ([latin capital V with dot above]O2) and energy expenditure (EE) during resistance training. The study investigated the effects of different RIs on [latin capital V with dot above]O2 and EE in resistance exercises performed with multiple sets and recruiting large and small-muscle mass. Ten healthy men performed 4 randomized protocols (5 sets of 10 repetitions with 15 repetition maximum workloads in either horizontal leg press [LP] or chest fly [CF] with an RI of 1 and 3 minutes). The [latin capital V with dot above]O2 was measured at rest, within sets, and during 90-minute postexercise recovery (excess postexercise oxygen consumption [EPOC]). The EE was estimated from [latin capital V with dot above]O2net (total [latin capital V with dot above]O2 - rest [latin capital V with dot above]O2). The [latin capital V with dot above]O2 increased in all protocols, being higher within the exercises and during EPOC in the LP than in the CF regardless of the RI. The 1-minute RI induced higher accumulated [latin capital V with dot above]O2 during LP (p < 0.05) but not during CF. The EPOC lasted approximately 40 minutes after LP1, LP3, and CF1, being longer than after CF3 (20 minutes, p < 0.05). Total EE was mainly influenced by muscle mass (p < 0.001) (LP3 = 91.1 ± 13.5 kcal ~ LP1 = 88.7 ± 18.4 kcal > CF1 = 50.3 ± 14.4 kcal ~ CF3 = 54.1 ± 12.0 kcal). In conclusion, total [latin capital V with dot above]O2 was always higher in LP than in CF. Shortening RI enhanced the accumulated fatigue throughout sets only in LP and increased [latin capital V with dot above]O2 in the initial few minutes of EPOC, whereas it did not influence total [latin capital V with dot above]O2 and EE in both exercises. Therefore, (a) the role of RI in preventing early fatigue seems to be more important when large-muscle groups are recruited; (b) resistance exercises recruiting large-muscle mass induce higher EE because of a greater EPOC magnitude.
