Chronic Effects of Different Rest Intervals Between Sets on Dynamic and Isometric Muscle Strength and Muscle Activity
José Claudio Jambassi Filho1, André Luiz Demantova Gurjão, Marilia Ceccato
1From the Department of Physical Education, Institute of Biosciences, São Paulo State University (JCJF, ALDG, MC, AKGP, LHG, SG), and School of Physical Education and Sport, University of São Paulo (JCJF), São Paulo; Department of Physical Education, Federal University of São Francisco Valley, Petrolina, Pernambuco (ALDG); Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul (AKGP); and Federal University of Paraná, Curitiba, Paraná (LHG), Brazil.
Objective:
This study investigated the chronic effects of different rest intervals (RIs) between sets on dynamic and isometric muscle strength and muscle activity.
Design:
We used a repeated-measures design (pretraining and posttraining) with independent groups (different RI). Twenty-one resistance-trained older women (66.4 ± 4.4 years) were randomly assigned to either a 1-minute RI group (G-1 min; n = 10) or 3-minute RI group (G-3 min; n = 11). Both groups completed 3 supervised sessions per week during 8 weeks. In each session, participants performed 3 sets of 15 repetitions of leg press exercise, with a load that elicited muscle failure in the third set. Fifteen maximum repetitions, maximal voluntary contraction, peak rate of force development, and integrated electromyography activity of the vastus lateralis and vastus medialis muscles were assessed pretraining and posttraining.
Results:
There was a significant increase in load of 15 maximum repetitions posttraining for G-3 min only (3.6%; P < 0.05). However, posttraining results showed no significant differences between G-1 min and G-3 min groups for all dependent variables (P > 0.05).
Conclusions:
The findings suggest that different RIs between sets did not influence dynamic and isometric muscle strength and muscle activity in resistance-trained older women.
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