Do you need to train to muscle failure for maximum muscle growth?

Muscle growth depends more on total training volume than on the point at which you end a set. Two large analyses combining dozens of studies find no meaningful difference in muscle growth between training to muscle failure and stopping before failure, as long as the total work remains the same. This also applies specifically to complete muscle failure, the point at which you truly cannot complete another repetition.

One analysis does suggest that training closer to your limit produces slightly more muscle growth. But the relationship is small, and estimates of how many repetitions were 'still left in the tank' are inherently uncertain. In people who were already trained, a closer look at one part of the data showed a small advantage for training to failure (effect size 0.15), but that is a modest finding from a single sub-analysis, not a broadly supported conclusion.

One specific study with trained men and women who performed one set per exercise found that stopping with two repetitions in reserve and continuing to failure produced comparable gains in strength and endurance. On a few measures of muscle growth, training to failure tended to be slightly more favourable, but the absolute differences were small.

What does make a difference: if your training volume drops when training to failure because you accumulate more fatigue, you will actually make less strength progress than someone who stops a little earlier on a regular basis. The same pattern holds for explosive power. It therefore pays to keep performing enough sets rather than pushing every set to the absolute limit.

Advanced techniques such as drop sets or rest-pause sets also offer no clear additional benefit when volume is matched. For maximum strength gains (one-repetition maximum), heavy weights are always superior to light ones, regardless of whether you train to failure. For muscle growth, a wide range of weights works well, as long as total effort and volume are right.