Do I need to train to muscular failure?

Training to muscular failure, otherwise known as momentary failure (i.e., the point at which another concentric repetition cannot be completed with proper form), is not necessary to increase muscle strength.^[1] In fact, ending each set a few reps shy of failure appears to be superior to training to failure for maximizing gains in 1RM strength.^[2][3]

In contrast, training closer to failure appears to be better for increasing muscle size in a dose-response manner,^[4] meaning that on a per set basis, a set performed to failure is the most conducive to muscle gain. However, this relationship appears to be influenced by load.

When using light loads (30%–40% of 1-repetition maximum), sets should be performed to failure to maximize muscle gain,^[5] but as the load gets heavier, training to failure becomes less important.^[4] Further research on the relationship between load, proximity to failure, and muscle gain is needed, but evidence suggests that in the context of heavy loads (≥80% of 1-repetition maximum), training to failure and stopping a set several reps shy of failure produce similar muscle gain.^[6]