The overload principle contends our bodies adapt when a sufficient stimulus is applied. The adaptive capacity evolves as our training improves and the stimulus must strengthen to force further adaptation. With resistance training, traditional programming focuses on increasing the load or magnitude of resistance to further adaptation. Over the last decade, we have accrued more evidence showing high repetition can yield similar hypertrophy outcomes and low and moderate repetition, begging the question, does resistance need to change for progressive overload? This study compared two protocols: one that progressed resistance only and one that progressed repetitions only.
The protocol focused on lower extremity exercise with four sets of four exercises: free-weight back squat, leg extension, straight-leg calf raise, and seated calf raise. The participants completed 2 sessions per week for 8 weeks. Each group started with sets of 8-12 reps and performed sets to failure with 2 min rest between sets. The results showed both groups had equivalent improvements in hypertrophy and countermovement jump. Strength improvements slightly favored the LOAD group while endurance (max number of reps) slightly favored the REPS group.
This study adds to the growing body of evidence showing there are many ways to hypertrophy muscle effectively. There are no magical rep ranges but the effort does need to be high. How many times are patients going to or very near failure? If adding muscle is the goal, they need to approach failure, regardless of the load.