Short rest between sets may blunt muscle growth?

Do short rest periods between sets blunt muscle growth?

Short rest periods (i.e. ≤ 1 min) between sets are popular in the gym. It is sometimes suggested that short rest periods may be beneficial because they stimulate a larger increase in circulating anabolic hormones (e.g. testosterone) compared to longer rest periods.

However, the hormonal response immediately after resistance exercise is not related to muscle growth (the increase is too small and short to matter). Therefore, it can questioned whether short rest periods between sets are indeed better, or maybe even worse, for muscle growth.

This study compared the effects of a 1-min rest period with a 5-min rest period between sets on muscle protein synthesis (the process driving muscle adaptation). Subjects were recreationally resistance-trained males. All subjects performed 4 sets to failure with 75% of their 1-repetition maximum on both the leg press and leg extension.

Not surprisingly, the 1 min rest period protocol resulted in 13% less total training volume.

However, the 1 min rest protocol resulted in 37% lower muscle protein synthesis rates compared to the 5-min rest protocol.

Of course, short rest periods are time efficient. A practical option could be to alternate between exercises for different muscle groups (also known as ‘supersets’). This will allow time efficiency and sufficient rest for each muscle.

Study:
McKendry et al. Short inter-set rest blunts resistance exercise-induced increases in myofibrillar protein synthesis and intracellular signalling in young males. Exp Physiol, 2016

Go to the next infographic in the resistance exercise series:
Switching up training variables is unnecessary?