Do You Need to Train to Failure to Build Muscle?

You are three reps into a hard set of squats. Your legs are burning, the bar drags on every rep, and the same voice pushes you on. Keep going until you cannot move it. That is the rule you learned early. No pain, no gain. If you did not hit failure, the set did not count.

It is an exhausting way to lift, and it can leave you sore for days, nervous about heavy sets, and unsure whether all that grinding is building anything. The good news is that the research on this question is now large and consistent, and it points to a calmer, safer way to train that works as well for most people.

What training to failure means

Muscular failure is the point in a set where you cannot complete another rep with good form, no matter how hard you push. Stop one rep before that and you have one rep in reserve. Stop three reps before it and you have three in reserve. That number, your reps in reserve, is a simple way to describe how close to the limit you took the set.

For years the assumption was that closer to failure is better, and that the last few grinding reps were where the real growth happened. That idea is worth checking, because training to true failure is hard. It raises fatigue, lengthens recovery, and on heavy compound lifts it can push your form to breaking point at the worst possible moment.

What the research shows

Two large evidence reviews have pooled the trials that pit failure against stopping short. In the Journal of Sport and Health Science in 2022, Grgic and colleagues combined studies comparing failure with non-failure training. Across the pooled data they found no meaningful difference in strength, with a standardized effect of minus 0.09, and no clear difference in muscle size overall. Their conclusion was direct. Training to muscle failure does not seem to be required for gains in strength and muscle size.

In Sports Medicine in 2023, Refalo and colleagues reviewed 15 randomized controlled trials that varied how close people trained to failure. They found only a trivial advantage for going to failure for muscle growth, with a standardized effect of 0.19. The amount of weight lifted and the number of hard sets did not change that picture. They pointed to getting close enough to failure and doing enough total sets as the drivers of growth, rather than hitting failure itself.

A 2025 randomized controlled trial in Medicine and Science in Sports and Exercise put this to the test directly. Hermann and colleagues had 42 trained men and women perform single sets either to failure or with two reps in reserve. Strength gains were similar between the two groups. A few measures of muscle size leaned slightly toward the failure group, but the differences were modest. This suggested that short, submaximal sets can build muscle and strength efficiently, and that pushing to failure is optional rather than essential.

There is a small caveat. In the pooled data, well trained lifters saw a slight muscle-growth edge from training closer to failure, on the order of a 0.15 standardized effect in the 2022 review. That is a minor advantage rather than a large one, and it has to be weighed against the extra fatigue and risk that failure brings.

Why stopping short can serve you better

If the muscle and strength results are close, the deciding factor becomes everything around the set. Training to failure costs more than the reps you see. It raises muscle damage and soreness, which can drag down the quality of your next few sessions. It makes each set feel much harder, so you are more likely to cut your workout short or skip the gym the next day.

It also changes your form. On a heavy squat, deadlift, or bench press, the final failing rep is where technique falls apart and where most avoidable strains happen. Leaving one to three reps in reserve keeps your positions sharp and lets you finish the session strong. Because each set is less draining, you can usually do more good, clean sets across the week, and total hard sets are one of the clearest drivers of growth in the research.

How hard your sets still need to be

Stopping short only works if you still train with real effort. The evidence suggests that sets taken nowhere near failure, with five or more reps left in the tank, grow muscle less well. The sweet spot for most working sets is one to three reps in reserve. That means you end the set knowing you had a rep or two left, not five, and not zero.

Judging reps in reserve takes practice. A useful trick is to occasionally take a single set of a machine exercise to true failure so you learn what your genuine limit feels like. Then use that memory to place your other sets one to three reps short of it. Over a few weeks, your estimate becomes accurate, and you can push hard without gambling on form.

How to put it into practice

Common mistakes

The first mistake is sandbagging. Leaving five or more reps in reserve feels comfortable, but that is too little effort to build muscle well. Effort still has to be high. The second mistake is the opposite, taking every set of every exercise to failure and burying yourself in fatigue, which usually means fewer quality sets later in the week. The third is chasing soreness as proof of a good workout. Soreness reflects damage and novelty, not growth, so a workout that leaves you less wrecked is not a worse one.

Frequently asked questions

The bottom line

You do not have to grind every set into the ground to build muscle and strength. The research is now clear that stopping one to three reps short works about as well as training to failure for most people, and it comes with less fatigue, cleaner form, and lower injury risk. Train with real effort, leave a rep or two in the tank, add a little over time, and let consistency do the heavy lifting.

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