The generally accepted formula for developing muscle size is to perform 4 sets of 10 reps using 70% of your one rep max (1RM) with a rest period of 90 seconds between sets. If it’s strength you’re trying to build, experts might suggest decreasing the volume to 4 sets of 6 reps while increasing the weight to 85% of 1RM and giving yourself 5 minutes of between sets rest.

How different are these routines? A study published in the Journal of Strength and Conditioning Research compares the physiological responses. Measurements of 6 experienced male weight lifters taken 20 minutes before and an hour after completing these routines showed no differences in muscle activity, rate of force production or peak force. Hypertrophy (muscle size) training increased blood lactate and decreased pH to a greater degree than strength training, and the electrolyte response was also different.

True Strength Moment: Strength training is probably going to increase the size of your muscles just as hypertrophy training is likely to boost your strength. Switching between these different routines every month or so might be an effective approach to rounding out your weight lifting program.