Training to Failure: How Close Do You Need to Go?

Training to failure and muscle growth: what the research says

Several reviews have now pooled the studies.

• Failure versus stopping short: a near draw. A 2022 meta-analysis by Refalo and colleagues in Sports Medicine pooled 15 studies. Training to failure gave at most a trivial advantage for muscle growth, and when only true momentary failure was compared with non-failure training, there was no clear advantage. The authors suggested the link between how close you go and how much you grow may not be a straight line.
• A similar result from another team. A meta-analysis by Grgic and colleagues in the Journal of Sport and Health Science (2022), also covering 15 studies, found no significant difference in muscle growth or strength overall, and concluded that training to failure "does not seem to be required". In the studies of resistance-trained people, failure showed a small advantage for growth, so it may matter a little more as you get experienced.
• Closer is better, up to a point. A 2024 analysis by Robinson and colleagues in Sports Medicine estimated reps in reserve across many studies. Muscle growth improved as sets ended closer to failure, but strength gains were similar across a wide range of effort. For strength, the weight on the bar seemed to matter more than how close to failure you went.
• In trained lifters, one or two reps short grew as much as failure. In a 2024 study in the Journal of Sports Sciences, Refalo and colleagues had 18 resistance-trained men and women train one leg to failure and the other leg stopping 1 to 2 reps short, for eight weeks. Both legs grew by almost exactly the same amount, but the failure leg consistently showed more signs of fatigue during sessions, such as slower reps.

Put together: getting close to failure matters, but the final rep or two adds little. Stopping five or more reps short probably leaves growth on the table. Pushing through to absolute failure on every set adds little more and costs you recovery.

The cost of going all the way

Failure is not free. In a 2017 study in the European Journal of Applied Physiology, Morán-Navarro and colleagues had ten resistance-trained men do the bench press and squat with the same weight and the same total reps, either to failure (3 sets of 10, with a weight they could lift only 10 times) or not (6 sets of 5). After the non-failure sessions, performance had largely recovered within 6 hours. After the failure session, the authors found recovery was slowed by up to 24 to 48 hours, with higher markers of muscle damage.

That matters because fatigue carries over:

• Within a session: a set to failure often costs reps on the next set, so total quality work can drop.
• Between sessions: if you train the same muscles again two or three days later, slower recovery means weaker sessions.
• On a diet: when food is low and recovery is harder, extra fatigue is even more expensive.

The 2022 Grgic review also found that when failure training was not matched for total volume, non-failure training actually produced more strength. More exhausting does not mean more effective.

You are probably further from failure than you think

Rating reps in reserve is a skill. A 2022 review by Halperin and colleagues in Sports Medicine pooled 12 studies with 414 people and found that, on average, people underpredicted the reps they had left by about 1 rep. Predictions were better with heavier weights, and training experience did not make much difference.

If you think you stopped "two short", you may well have had three or more left. Two ways to calibrate:

1. Now and then, take the last set of a safe exercise to failure. A leg extension, a machine press or a cable row works well. If you predicted 2 reps left and got 5 more, you know to push harder.
2. Use your training log. If you hit the top of your rep range on every set, every session, your weights are probably too light for the effort you think you are giving. Progressive overload explained shows how to move the weight up.

When to go to failure, and when not

Situation	Going to failure	Why
Machine and isolation exercises (leg extensions, curls, lateral raises)	Fine, especially on the last set	Low risk when form breaks down, and less fatigue overall
Heavy barbell lifts (squats, deadlifts, bench press without a spotter)	Usually avoid	Form can break down at the end of a set, and recovery suffers more
Beginners	Usually avoid	Learning good technique matters more, and stopping a couple of reps short still works well
On a diet	Use sparingly	Recovery is harder when food is low
Last set of an exercise	Reasonable	No later sets for the fatigue to spoil

A simple way to apply it

• Most working sets: stop about 1 to 3 reps short of failure (RPE 7 to 9). In the Refalo 2024 study, stopping 1 to 2 reps short built as much muscle as going to failure.
• Big barbell lifts: stay at the safer end of that range.
• Machines and isolation work: go closer, with the occasional set to failure to check your judgement.
• Count only hard sets towards your weekly total (see how many sets per week to build muscle). A set stopped with many reps left counts for less.
• Keep your effort honest, not heroic. Grinding out ugly reps does not count for more.

If your lifts are going backwards and every set feels like a battle, too much failure may be part of the problem. A lighter week can help clear the fatigue: see deload week: what it is and when you need one.

Where coaching helps

Most people either stop too far from failure without realising it, or go to failure on everything and wonder why they feel flat. Both are easier to spot from the outside.

With one-to-one coaching from CoachAk, your program sets out the sets, reps, effort target (RPE or reps in reserve), rest time and coaching cues for every exercise, built around your experience, equipment and injury history. You log every workout in the app, and you can send form-check videos for your coach to reply to, so technique and effort can be checked on real sets. Each weekly check-in covers your training adherence, sleep, energy and stress, and your coach's written feedback explains what changes next week and why.

If you want to know your sets are hard enough without burying yourself, apply for coaching, or read more about muscle gain coaching.