Effects Of Short Vs. Long Rest Period Between Sets On Elbow-Flexor Muscular Endurance During Resistance Training To Failure

Journal of Strength and Conditioning Research, 2007, 21(4), 1320–1324 2007 National Strength & Conditioning Association

Research Note

EFFECTS OF SHORT VS. LONG REST PERIOD BETWEEN SETS ON ELBOW-FLEXOR MUSCULAR ENDURANCE DURING RESISTANCE TRAINING TO FAILURE
´ ´ ´ ´ DAVID GARCıA-LOPEZ,1 JOSE A. DE PAZ,2 ERNESTO MONEO,2 RODRIGO JIMENEZ-JIMENEZ,2 ´ 2 3 GUILHERME BRESCIANI, AND MIKEL IZQUIERDOFaculty of Health Sciences, European University Miguel de Cervantes, Valladolid, Spain; 2Department of Physiology, University of Leon, Leon, Spain; 3Studies, Research and Sport Medicine Center, Government of ´ ´ Navarra, Navarra, Spain.
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ABSTRACT. Garcıa-Lopez, D., J.A. de Paz, E. Moneo, R. Jimenez´ ´ ´ Jimenez, G. Bresciani, and M. Izquierdo. Effects of short vs. long ´ rest periodbetween sets on elbow-flexor muscular endurance during resistance training to failure. J. Strength Cond. Res. 21(4):1320–1324. 2007.—This study aimed to examine shortterm resistance training effects of resting period length between sets on maximal number of repetitions and mean velocity over a moderate-intensity (60% of the maximum voluntary isometric contraction [MVIC]) set to failure on elbow-flexormuscles. The MVIC and surface electromyographic activity (sEMG) were also measured. Twenty-one untrained subjects were divided into 3 groups: short rest between sets (1 minute; SR), long rest between sets (4 minutes; LR), and nontraining control group (CG). The SR and LR performed 3 sets to failure in an arm-curl machine, 2 days per week for 5 weeks, with moderate loads (60–75% of the MVIC). The LRcompleted a significantly higher (31.6%, p 0.05) total training volume than the SR. Both training groups enhanced the maximal number of repetitions to failure, with no significant differences in the magnitude of gains. The posttraining average velocity achieved by the SR at 40, 50, 60, 70, 80, and 90% of the total number of repetitions completed was significantly higher (p 0.05) than thecorresponding average velocity achieved on pretraining conditions, whereas no significant differences were observed in the LR. No significant changes in the MVIC or sEMG were observed in any group. We conclude that short-term elbow-flexor resistance training to failure, allowing 1 or 4 minutes of rest between sets, induces similar gains concerning local muscular endurance. Nevertheless, only the SR trainingapproach reduced the rate of decline in the average repetition velocity during a set to failure. This can be of some importance in sport modalities in which not only the maximal number of repetitions (e.g., muscle endurance), but also a greater maintenance of high repetition velocities, may be critical for performance. KEY WORDS. biceps brachii, average repetition velocity, local muscular endurance,short-term resistance training

power, and local muscular endurance (2, 12, 14). Strength training that consists of moderate-length resting periods (2–3 minutes) between sets has been shown to lead from moderately higher to similar strength and muscle mass gains compared with short resting periods (SR; 30–60 seconds) (2, 12, 14). Thus, the role of the amount of rest between sets to failure tooptimize muscle performance remains unclear. In addition, performance in several sport modalities is not only related to performing a high number of repetitions with a submaximal pretraining load, but also to maintaining a high repetition velocity along a given exercise (4, 5). In this line, the impact of resting period length manipulation after a short-term resistance training (i.e., 5 weeks) onrepetition velocity declines during a moderate-intensity bout remains to be elucidated. In light of these observations, we hypothesized that a training approach with SR periods between sets would result in a higher fatigue state, providing subsequently favorable conditions for improving local muscular endurance and sustained repetition velocity over a set of repetitions to failure. Therefore, the...