Exploring the Dose–Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions

If you lift weights until you're almost too tired to do another rep, you'll likely build bigger muscles—but your strength gains won't be any better than if you stopped earlier, as long as you're doing the same total amount of work and lifting the same weight.

When you lift weights and push yourself almost to the point of not being able to do another rep, you’re more likely to build bigger muscles than if you stop earlier — even if you’re lifting the same weight or doing the same number of sets.

If you lift weights with different levels of effort—whether you stop just before failure or push almost to failure—you’ll still gain about the same amount of strength, as long as you’re doing the same total amount of work and using the same weight.

We don't really know for sure if doing exercises with more or fewer reps left in the tank helps you build more muscle, because scientists are just guessing how many reps people had left based on how the studies were written.

When you lift weights close to your limit, your muscles grow bigger better if you leave a few reps in the tank—but that same closeness doesn’t help you get stronger as much, which suggests your body builds muscle and strength in different ways.

People who want to get stronger might need to train differently than people who want to build bigger muscles, but we don’t have good ways to measure how close to failure they should go—so right now, it’s hard to give clear advice on how to train for each goal.