Our current analysis shows that lengthened partial reps, which are exercises performed only through the stretched bottom portion of a movement, appear to build muscle just as effectively as full range of motion reps. The evidence we have reviewed leans toward both training styles producing similar muscle growth when total weight and sets are matched.
We analyzed the available research and found that 108 studies support this comparison, while 0 studies refute it [1]. When we look at the specific claims we reviewed, the data suggests that lifting weights through a partial range that fully stretches the muscle yields the same growth over two months as lifting through a complete range [1]. This holds true as long as you move the same total weight and complete the same number of sets. We also found that combining full-range movements with lengthened partials works just as well as sticking strictly to full-range lifts [2]. Consistency in your training routine matters more than picking one specific style.
What we have found so far points to a flexible approach for building muscle. The evidence we have reviewed leans toward the idea that you do not need to force yourself into full range of motion reps if you prefer partials that emphasize the stretch. Our current analysis shows that muscle growth responds to the total work you put in, not just how far you move the weight. We are still gathering more data, and our understanding will continue to improve as new studies come to light.
For your next workout, focus on moving the weight with control and hitting the same total reps and sets you normally would. You can safely shorten your range of motion to emphasize the stretch, or stick to full movements, and expect similar results over time.
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