Performing resistance exercises with effort close to muscular failure leads to increases in both the contractile proteins and the fluid-filled components of muscle cells.

We analyzed the available evidence and found that performing resistance exercises near muscular failure is associated with increases in both the contractile proteins and the fluid-filled components of muscle cells [1]. This suggests that training close to failure may stimulate changes in two key parts of muscle tissue: the myofibrillar structures responsible for force production, and the sarcoplasm, which contains water, glycogen, and other non-contractile elements. What we’ve found so far is based on one assertion supported by 54 studies or data points, with no studies contradicting this observation. The evidence we’ve reviewed leans toward the idea that pushing sets close to failure triggers adaptations in both areas of the muscle cell. This doesn’t mean every person will respond the same way, or that failure is the only way to achieve these changes — only that, within the data we’ve examined, this pattern appears consistently. In practical terms, if your goal is to encourage growth in both the strength-related and size-related parts of your muscles, training with high effort — where you’re very close to not being able to complete another rep — may be one way to do it. But we don’t yet know if this is necessary, or if lighter training with more volume could produce similar results. Our current analysis is limited to the single assertion provided, and more research could refine or expand this understanding.