Going all the way to exhaustion on every set probably doesn't build more muscle than stopping a few reps short — both seem to work about the same.
Evidence from Studies
Supporting (2)
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Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis
The study compared lifting until you can't do another rep versus stopping a few reps early, and found both build similar amounts of muscle.
The study found that going all the way to failure on each set doesn’t make your muscles grow more than stopping just short of failure, as long as you do a similar amount of work.
Contradicting (1)
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Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training
The study found that lifting heavy weights to the point of failure doesn’t build more muscle than stopping a few reps short, as long as the weight is heavy. So, going to failure every time isn’t necessary for similar muscle growth.
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