Are Half Reps the Muscle Hack Lifters Have Overlooked? Here’s What the Research Says

The debate on whether half reps work is right up there with whether low-carb diets actually help you lose weight. Some people swear by them, while others stand in the corner of the gym snickering about ego lifting. But as it turns out, the gym bros might’ve had it right all along—half reps could actually help boost muscle growth when used properly, new research says.

The study, published in SportRχiv, followed 23 trained participants who completed unilateral calf raise training on a Smith machine twice a week for eight weeks. 

At the beginning of the study, participants were broken up into two groups: one group that performed half reps at the beginning of the set and another that performed full range of motion reps until failure and then added partial reps afterward. Muscle thickness of the inner calf was measured via ultrasound before and after each workout. 

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Researchers found that both training methods led to moderate to significant increases in muscle mass. While initial half reps resulted in a slightly greater increase compared to half reps done after muscle failure, the results weren’t conclusive. With this, more research is needed to identify if half reps prior to regular sets are totally necessary. 

While the study shows that initial half reps are just as effective at building muscle as post-failure half reps, there are a couple of caveats. For one, the sample size was small—just 23 participants—so a larger group would be needed to draw any big conclusions. And while there was an increase in muscle growth, it was pretty minimal, meaning more time and research are needed to really prove how effective initial half reps are. One thing is for sure though: If you can only crank out half reps at a certain point in your workout, it's probably still worth it.