Training to volitional discomfort (stopping 1–3 repetitions short of failure) during low-load resistance training produces the same degree of muscle hypertrophy as training to momentary muscular failure.

Study: Effect of resistance training to muscle failure vs non-failure on strength, hypertrophy and muscle architecture in trained individuals

In this study, people lifted light weights either until they couldn’t do another rep or stopped just before that point—and both groups ended up with nearly the same muscle growth. So you don’t need to push to total exhaustion to build muscle.

Study: Low-Load Resistance Training Performed to Muscle Failure or Near Muscle Failure Does Not Promote Additional Gains on Muscle Strength, Hypertrophy, and Functional Performance of Older Adults

When older adults lifted light weights, it didn’t matter whether they stopped just before exhaustion or pushed until they couldn’t do another rep—both groups got just as strong and their muscles grew similarly.

Study: Low-Load Resistance Training to Volitional Failure Induces Muscle Hypertrophy Similar to Volume-Matched, Velocity Fatigue

When lifting light weights, you don’t need to push until you can’t move anymore to grow muscles—stopping just before total exhaustion works just as well, as long as you’re working hard enough.