Training to Failure: Is It Necessary for Muscle Growth & Strength?

Many lifters and bodybuilders swear by training to failure, while others think it’s the beeline to injury and overtraining.

The truth is somewhere in the middle: it can help you build muscle, but it can also slow your recovery and make your training feel harder than it needs to be.

Let’s talk about what failure means, when it helps, when it hurts, and how you can use it in your training.

What Does Training to Failure Mean?

Training to failure usually means doing reps until you cannot complete another one with acceptable technique.

But there are a few flavors of failure.

There are also other types of failure, like:

• Systemic failure: breathing or whole-body fatigue makes you give up before your target muscles fail. Try an AMRAP (as many reps as possible) set of squats at 50% of your 1RM, and you’ll know what I mean.
• Pain or psychological failure: you fail because the set becomes too uncomfortable. In theory, you might have had another rep; in practice, your brain says “done.”

Here, I’m going to focus on muscular failure, not other things that might force you to stop a set.

Reps in Reserve

A related concept is reps in reserve, or RIR.

• If you stop a set when you could have done two more reps, that was 2 RIR.
• If you could have done one more, that was 1 RIR.
• And if you couldn’t have done another rep, that was 0 RIR.

Most people are pretty bad at estimating their RIR (although your accuracy improves with training experience), so when you think you have 1 rep left in the tank, you might, if you absolutely, positively had to, be able to crank out 2 or 3 more.¹

That’s actually one reason why training to failure can help: if you stop at what you estimate is 3 reps away from failure, you might actually be stopping 5 reps away, and that would be too far away to build much muscle.

Why Training to Failure Works

The closer you push a set to failure, the more motor units you recruit.

Your body won’t activate so-called high-threshold motor units (the ones attached to the biggest and most growth-prone muscle fibers) unless it has to.²

Training with heavy weights forces it to do so. And so does training to failure.

When you use heavy weights, your body has to recruit these high-threshold motor units much earlier, often from the first rep, because the demand for a lot of force is high right away.

For example:

• A 5-rep max set: the weight is so heavy that you need your high-threshold fibers immediately.
• A 20-rep set: your body recruits more and more high-threshold fibers until the last several reps require most of them.

That’s one reason why you can build muscle with both heavy and light weights, as long as you take the lighter set close to failure.

Now, fiber recruitment is not the whole story. You also have to put the recruited fibers through enough mechanical tension for enough total work to make them grow.

Let’s talk about that.

Training to Failure for Muscle Growth

The biggest driver of muscle growth is mechanical tension: your muscle fibers producing force under load.³

As you get close to failure, your muscle fibers have to work very hard, creating a lot of mechanical tension, even if the weight isn’t very heavy. And those final reps create a strong signal for growth.

That’s the idea of “effective reps”: easy sets where you stop far from failure are not very good for building muscle, but the effective reps close to failure are.

Basically, current research suggests that there is a small but meaningful benefit to training close to failure for building muscle, as long as you can recover from doing so.

That aligns very well with what I have noticed over 40 years of training and 30+ years of coaching: you have to train hard to grow.

Do you have to train to failure all the time? Or even most of the time?

Definitely not, and I’ll talk about the potential drawbacks in a bit.

You could say that going close to failure makes sure you train hard enough to get to the most effective reps. But it’s certainly not a requirement for building muscle.

Failure Is More Important With Lighter Weights

The lighter the weight, the more important it becomes to approach failure.

Recent research shows that you can get similar muscle growth with both light and heavy weights. Anything from around 5 reps to 30+ reps works.^{8 9 10}

However, if you want to go the lighter route, you have to get close to failure. With heavy weights, you don’t.

If you use a weight you can only manage 5 reps with, even stopping at 3 reps is still relatively heavy and demanding. But if you’re lifting a weight you could do for 25 reps, and you stop at 15, you haven’t created much of a muscle-building signal at all.

• So, for low reps and heavy weights, you can stay pretty far from failure and still get an effective muscle-building workout.
• For moderate reps, getting within a few reps of failure works great.
• For high reps, you need to get very close to failure.

That’s also why a middle ground of 6–15 reps is still the best range for muscle growth. You don’t get the joint stress and potential injury risk of super heavy training, and you also don’t get the immense discomfort of training to failure with high reps.

Read more:

>> How Many Sets and Reps Should You Do to Build Muscle?

Training to Failure for Strength

For getting strong, training to failure is not necessary and not better than stopping a few reps short of failure.

Strength does depend on muscle size, but it’s also a skill. To get as strong as possible, especially in big lifts like the squat or bench press, you have to practice that skill, lifting heavy reps with good technique. And get enough recovery to repeat that process.

Training to failure is less important for that process and often less useful. It can even interfere with it.

When you take heavy compound lifts to failure often, fatigue builds up. Your rep quality drops, and the bar speed slows. Your later sets suffer. Even your next session might suffer.

Over time, you might end up accumulating fewer high-quality heavy reps because you spent so much energy trying to reach failure. Plus, the risk of injury increases when you push really heavy weights to failure, and your form might break down.

The Downsides of Training to Failure

So, if you get similar results from training to failure as from not training to failure, is there a reason you shouldn’t, besides “it’s harder”?

Fatigue Build-Up

The biggest reason is fatigue. Training to failure doesn’t overtrain you overnight, but it does create more fatigue for a stimulus that’s not automatically better.

That’s more fatigue you have to recover from, and if your recovery capacity can’t keep up, your progress will suffer. That’s especially important to keep in mind if you’re following a high-volume program.

Risk-Reward Ratio

In addition, the closer you get to failure, the harder it’ll be to maintain good form.

That might not matter much on lateral raises, but if you’re deadlifting or squatting, a wonky rep at maximum effort is how injuries happen.

CNS Cost

If you hit failure on every set of every session, you’ll likely find your performance dropping within a week or so. Not necessarily from muscle fatigue, but from central nervous system fatigue.

Even your motivation to train hard can take a nosedive.

Which Exercises Are Best for Failure?

Training to failure works best on stable and technically easy exercises.

They have less technical risk, and you can easily bail out of them if the last rep goes awry.

If your final rep of lateral raise is slow and sloppy, no one needs to call emergency services. If your final deadlift rep goes sideways, that’s a different story.

That doesn’t mean you can never push your compound lifts close to or even to failure. You can. But even disregarding the fatigue cost, there’s a big difference between a hard set of five squats with one rep in reserve and a failed last rep when it comes to injury consequences.

And if and when you train to failure, it’s often a good idea to do so at the end of your workout. Your early performance doesn’t suffer, and you still reap any potential benefits of failure. Plus, finishing with an all-out effort feels awesome.

How Close Should You Train to Failure?

Building on what we’ve talked about, let’s boil things down to concrete numbers.

If your main goal is to build muscle, it’s a good idea to end most working sets around 1 to 3 reps in reserve.

That’s close enough to failure for >95% of the muscle-building benefits, yet far enough away to manage fatigue. And realistic enough so you can repeat it week after week.

Then, you can sprinkle in true failure. One way is to take the last set of an isolation exercise to failure. For example, you might terminate your first few sets of leg extensions at 1–2 RIR, then take your last set to technical failure.

For strength, you probably want to stay clear of failure on your main lifts, with heavy barbell work ending with 1–3 reps in reserve, sometimes more. You can still go closer to failure on accessory work.

Beginners vs. Advanced

Beginners don’t need to train to failure. You’re learning technique and figuring out what hard training feels like. You’ll make just as good gains with 2–4 reps short of failure.

That being said, the fact that you don’t need it doesn’t mean you should avoid it altogether. The ability to push a set hard is a skill in and of itself, and you won’t develop it without practice.

So, it can still be useful to take a safe exercise to failure. Try it on leg extensions or biceps curls for example. Learn what a really hard set feels like.

As an advanced lifter, you know your body and what good form looks like. You also need harder sets to keep progressing. Easy sets won’t do much when your body has adapted to years of training.

However, you’ll also create more fatigue because you can push harder and use heavier weights. A near-failure set of squats with 400 lb is another thing entirely than a 100 lb squat, even if both feel as heavy to different lifters.

With years of training experience, failure can be more useful, but you also have to be more disciplined about when not to use it.

A Nice Middle Ground for Intermediates

Here are my recommendations for intermediate lifters who want both size and strength.

Note that they’re based on what works in practice and on decades of experience, not lifted straight from any meta-analysis.

Lifts	Example Exercises	RIR	Notes
Main compound lifts	Squats, bench Presses, deadlifts, overhead presses	2–3	The last rep should slow down but not grind to a halt.
Compound accessories	Romanian deadlifts, barbell rows, dips	1–2	Get close to failure but without form breakdown.
Isolation and machine work	Curls, extensions, flyes, raises	0–1	Failure on final sets.

To Failure and Beyond?

Techniques like drop sets and rest-pause sets allow you to keep going after failure. You can also do partials once you’re unable to complete another full rep, and if you have a spotter, you can have them assist you.

So, why stop at failure when you can go beyond?

Well, the benefits are small, and you have costs (like fatigue and injury risk) to deal with.

• The big benefit is that you get a lot of effective work done in little time. Drop sets or rest-pause sets are fantastic when time is tight but you still want a maximally muscle-building workout.
• You get a lot of metabolic stress and muscle fiber fatigue. These things help drive growth, according to some research, even though they aren’t as important as mechanical tension.

That being said, going beyond failure is not something you have to do, and it’s usually not superior to stopping at or just before failure.

If you cloned me and had one me go beyond failure and another stopping just short, I doubt we’d see any huge differences, even if we’re talking years of training.

If you want take your failure training to the next level, I suggest you do so sparingly and mostly on isolation or machine exercises.

• A rest-pause set of cable lateral raises? Great.
• Bench press with a spotter? Sure, why not, on occasion.
• Heavy squats? Maybe not a top-notch idea.

My advice: use normal hard sets first and foremost. Add beyond-failure training only if and when they solve a problem (like limited time or limited equipment).

Sample Examples of Training to Failure

Here’s what two workouts, one bodybuilding-style workout and one strength-focused session, can look like if we implement what we’ve talked about so far.

Hypertrophy Example Workout

Imagine it’s Monday, and you’ve just arrived at the gym for chest day: bench press, incline dumbbell press, dips, and cable flyes.

You might bench for 3 sets of 5–8 reps, stopping around 2 reps in reserve. Then do incline presses for 3 sets of 8–12 reps, stopping around 1–2 RIR, followed by 3 sets of dips to around the same RIR. Then finish off with cable flyes for 3 sets of 15–20 reps, taking the final set to technical failure.

Heavy work stays heavy, and moderate work gets hard. Then you push isolation work, and leave with a great pump. You’ve done everything you need for maximum growth stimulus, but you haven’t buried yourself in fatigue for no good reason.

Strength Example Workout

Now imagine you’re trying to improve your squat.

You might do 3 working sets of 4–6 reps, leaving 2–3 reps in reserve. Then you add 3 sets of good mornings, plus 2 sets of split squats and leg curls, taking some accessory sets close but not all the way to failure.

You get high-quality squat practice first, followed by hypertrophy-style training and accessory work for the muscles that support your main lift. And you leave the gym fresh enough to do it over the same week.

Follow These Workouts in StrengthLog

The above examples are taken directly from our workout tracker app, StrengthLog. We’ve just walked through our free chest day workout and the very first workout of our intermediate squat program.

If you want to give them or one of our more than 100 workouts and programs for all training goals a try, feel free to download our free app.

It’s also the best way to log and track all your training so you get the results you’re working hard for.

Final Rep

If you’ve made it this far, you know you don’t have to train to failure, but that doing so can be a useful tool to pull out when you need it.

Getting close to failure is often enough for 95% of the muscle-building effect, and going for the remaining 5% might cost more than it’s worth. You don’t need to crawl out of the gym on your hands and knees to have a productive workout.

That said, training to failure isn’t a mistake, as long as you know why you’re doing it. Push close to the edge. Touch the edge when it makes sense. But don’t stick around there all the time.

Thanks for reading, and good luck with your training.

Want more?

Listen to episode 7 of The Strength Log podcast, where Daniel and Philip talk about training to failure, including dissecting a recent study and answering your questions.

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Last reviewed: 2026-05-29

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