In adults who regularly lift weights, performing workouts close to failure or with some reserve in the last rep produces similar improvements in how long they can sustain effort, with no meaningful...

We analyzed the available evidence on whether training close to failure improves endurance more than training with reps in reserve, and what we’ve found so far suggests no meaningful difference between the two approaches. In adults who regularly lift weights, workouts performed close to failure produced similar changes in how long they could sustain effort compared to workouts done with some reserve in the final rep [1]. This doesn’t mean one method is better for endurance — it means both appear to lead to comparable outcomes when it comes to stamina or time under effort. The evidence we’ve reviewed includes 60.0 supporting assertions and no refuting ones, but this doesn’t imply one approach is superior. Instead, it shows that whether someone pushes to near exhaustion or stops a few reps short, their ability to sustain effort over time tends to improve at a similar rate. We don’t know why this might be, or whether factors like training volume, frequency, or individual differences play a role. The studies we’ve reviewed focus on endurance outcomes, not strength or muscle growth, so we can’t say how these methods affect other goals. For someone focused on endurance, this means you don’t need to train to complete exhaustion to see gains. You can choose a level of effort that feels sustainable and still expect similar improvements in how long you can keep going. What matters most may be consistency — not how close you get to failure.