The effects of interset rest duration on performance and muscle activation during resistance training

The purpose of this study was to compare the effects of different rest intervals on performance and muscle activation during multi-joint (bent over row) and single-joint (biceps curl) exercises. Fifteen trained men that have experienced at least one year in resistance training were instructed to perform both exercises using three protocols in a randomized crossover design; each consisting of three sets with three different rest intervals; i) 60 seconds, ii) 90 seconds and iii) 120 seconds rest interval between sets. Each set was performed with hypertrophy designed loading (75% of 1RM) until fatigue. Results showed performing bent over row with 120 seconds rest interval produced higher number of repetitions and greater latissimus dorsi muscle activation compared to 60 seconds and 90 seconds rest interval. For biceps curl exercise, results showed 90 seconds and 120 seconds rest interval produced higher number of repetitions and greater biceps brachii muscle activation compared to 60 seconds rest interval. In conclusion, performing bent over row with 120 seconds rest interval interset and 90 seconds and 120 seconds rest interval during biceps curl exercise allow participants to produce greater lifting performance while recruiting more motor unit for activating the muscles in every set. The findings of this study is hoped to be used as a guideline for resistance training design planning in order to achieve optimum benefit while been time-effective.