The progressive training sessions with overloads are the most used strategies to elicit greater adaptive response to specific aims in strength performance. The total work with overload is a relevant factor in performance improvement. However, overload training affects mechanical muscular response, which triggers the onset of fatigue. The muscle fatigue reflects the loads characteristics (volume, intensity and recovery). In order to avoid the excessive fatigue while maintaining appropriate mechanical techniques, it is necessary to manipulate the recovery. Add more time between sets is the most applied strategy. According to the current researches, it seems that the best way to get both goals (less muscle fatigue and equal efficiency volume), is due to intra-set rest (ISR), which may be achieved by adding inter-repetition rest (IRR) in each repetition or cluster of repetitions within sets. These methodological approaches allow us to maintenance of technical characteristics (speed, strength, power) within many repetition-sets.
Grigoletto et al. (Tue,) studied this question.