Sport scientist Brad Schoenfeld did an experiment with 18 young men, who had been doing weight training on average for over three years. Schoenfeld divided the men into two groups, all of whom did a full body workout three times a week for eight weeks. The subjects did seven basic exercises: bench-press, military-press, lat-pulldown, cable-row, squat, leg-press and leg-extension. They did to-failure sets.
Half of the subjects trained using weights that were 70-80 percent of the weight at which they could just manage 1 rep [1RM]. Their sets consisted of 8-12 reps. [High load]
The other half of the subjects trained using weights that were 30-50 percent of the weight at which they could just manage 1 rep. Their sets consisted of 25-35 reps. [Low load]
Results
At the end of the eight weeks
both groups had gained the same amount of muscle mass. Apparently for muscle mass it makes no difference whether you train with relatively heavy or light weights.
The weight with which the subjects could just manage 1 rep [1RM] increased by more in the High load group than in the Low load group.
Conclusion
"Low-load training can be an effective method to increase muscle hypertrophy of the extremities in well-trained men", Schoenfeld concluded. "The gains in muscle size from low-load training were equal to that achieved with training in a repetition range normally recommended for maximizing muscle hypertrophy."
"On the other hand, if maximizing strength gains is of primary importance, then heavier loading should be employed at the exclusion of lower load training."
Source:
http://www.ncbi.nlm.nih.gov/pubmed/25853914
