From Ergo Log
Resistance training where you use weights with which you can manage 10-14 reps and take rests of several minutes in between probably results in just as much muscle growth as training that involves weight with which you can only manage 2-4 reps and one-minute rest periods. Sports scientists at the University of Central Florida write about this in Physiological Reports.
The researchers got ten well-trained men to train their legs on two different occasions by doing squats, leg presses, leg extensions, leg curs and calf raises.
On one occasion they did their weight sets at 70 percent of their maximal weight and rested for one minute between sets. [High Volume; HI] On the other occasion the men did their weight sets at 90 percent of their maximal weight and rested for three minutes between sets. [High Intensity; HI]
The researchers attached electrodes to the subjects’ leg muscles, which enabled them to see that the muscles had to work a little harder during the high-intensity workout. The difference was not significant, however.
The concentration of LDH [shown above] and myoglobin in the blood increased by more after the high-intensity workout than after the workout using lighter weights. LDH and myoglobin are markers for muscle damage.
The two workouts had no appreciable effects on the men’s IGF-1 or testosterone levels. The concentration of growth hormone rose by more after the high-volume workout than after the workout with heavier weights. The concentration of cortisol also rose by more after the high-volume workout than after the high-intensity workout.
The researchers measured the activity of anabolic signal molecules such as mTOR and Akt in the men’s leg muscles just before the workouts started and 1 and 5 hours after they had ended. Both workouts resulted in approximately the same increase in activity.
Strength training with relatively heavy weights [90 percent of your maximal weight] and short rests has different physiological effects than strength training with relatively light weights [70 percent of your maximal weight] and slightly longer rest periods. But both types of training probably stimulate muscle growth equally.
Physiol Rep. 2015 Jul;3(7). pii: e12466.