Resting longer (2-3 minutes) between sets can keep you stronger during workouts and is better for muscle growth.
Resting less (about 1 minute) between sets has been shown to lead to bigger boosts in growth hormone and testosterone, but resting longer keeps your strength up during training. But did either method boost muscle size more than the other? A recent study published in the Journal of Strength and Conditioning Research had untrained male subjects follow a 10-week weight-training program with rest periods between sets of either 1 minute or 2.5 minutes. The scientists measured the subjects’ arm sizes before and after the 10 weeks to determine which program resulted in greater gains in muscle size.
The group resting 1 minute between sets increased their arm size by 5%, but the group resting 2.5 minutes between sets increased their arm size by 12%.
To maximize muscle growth, rest 2-3 minutes between sets.
Since the study was done with novice lifters, beginners, in particular, should take note of their rest periods. Experienced lifters should rest 2-3 minutes between sets, but as with all the variables in workouts subject to change (weight, reps, exercises, sets, etc.), rest times should vary, occasionally going as low as 1 minute or less between sets. – FLEX