Key Takeaways

  1. Stretching has gotten itself a bad name in the fitness space, but most of the criticism is unjustified according to the most up-to-date research.
  2. If you want stretching to help rather than hinder, it’s important to manipulate variables such as when you stretch, how long your hold stretches for, and how intensely you stretch, depending on what you want to achieve.
  3. Keep reading to learn the best ways to incorporate stretching into your training routine so you can experience all the benefits without any ill effects.

You’ve probably heard that stretching is one of the pillars of an effective fitness plan, right up there with strength training and cardio. 

This same message is shared by personal trainers, group fitness instructors, and coaches around the world: 

You need to stay flexible to avoid injury, properly perform various exercises, and stay healthy into old age, and stretching is the best way to do this. 

Others disagree.

Some say that stretching isn’t all that important for improving your fitness, and that it can negatively affect your performance and might not be as helpful for protecting against injuries as was once believed. 

Others say that while stretching may have some merit in certain situations, it’s unnecessary for most people. 

Who’s right? 

Is stretching really an essential aspect of an effective fitness routine, or is it just an outdated ritual based on faulty past assumptions, like the idea we need to eat immediately after every workout or that doing more reps automatically leads to more muscle growth

You’ll learn the answer in this article. 

Specifically, you’re going to learn why people think stretching is important, whether or not stretching helps increase flexibility, prevent injuries, improve performance, and boost recovery and muscle growth, and the right (and wrong) ways to stretch, if you decide to do so.

Let’s dive in.

Why Do We Stretch?

dynamic stretching before workout

The main reason most people stretch is because they think it will reduce their risk of injury.

Specifically, the thinking goes that injuries are often caused by your muscles or tendons becoming tight, and this tightness can lead to all manner of problems during exercise.

For example, many people believe that a tight IT band is more likely to “rub” against other structures on the side of your knee when squatting, cycling, running, and so forth, and that this leads to IT band pain.

Others think that tight hamstrings are more likely to tear when running, and thus stretching helps keep your hamstrings supple and less susceptible to tearing. 

People apply the same line of thinking to pretty much every muscle and tendon in the body: if it’s tight, it’s more likely to rub, snap, or tear during exercise, leading to a number of different injuries. 

Another common reason people stretch, is they think it will help them maintain proper technique during various weightlifting exercises. They believe that the reason their technique falters is because a tight muscle or muscles prevents them from properly executing various exercises.

For example, many people believe that the reason they can’t keep their back straight during deadlifts is due to tight hamstrings, and so they’ll stretch their hammies to improve their deadlift form.

Then, there are also some people who claim that stretching between sets can increase muscle growth, and that stretching after workouts can help you build more muscle. 

So . . . how much of this is true, and how much of it is a bit of a stretch (harhar)?

Keep reading to find out. 

Summary: The main reasons people stretch are to avoid injury, improve weightlifting technique, and improve muscle growth and recovery.

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Stretching and Flexibility

Many of us believe that we aren’t as flexible as we should be—our short and tight muscles stop us from moving correctly.

Tight shoulder muscles keep us from standing up straight. Tight back muscles are why we can’t keep our backs straight while we deadlift. And tight hamstrings, glutes, and quads are why our butts stick out and our knees cave inwards when we squat

That’s the theory, at least.

It’s easy to see why people believe this: when we experience some kind of physical limitation, it often feels like our muscles are “tight,” and “short,” as if they aren’t quite long enough to allow us to move the way we want to. 

And when we stretch, we get more flexible.

That is, stretching helps us increase our range of motion and allows us to hold positions that weren’t possible only a few weeks before. For example, although many people aren’t flexible enough to touch their toes, most can fix this with a few weeks of stretching. 

So, stretching must “lengthen” and “loosen” our muscles, right? And this increased flexibility must improve our fitness, yes? 

Well, not really. 

The reason stretching makes you more flexible isn’t because it literally stretches your muscles. That is, it doesn’t make your muscles or tendons any longer, looser, or more pliant. Instead, stretching just trains your brain to tolerate the sensation of your muscles being forced into a stretched position.

At any given time, your brain has an idea of how far you can safely extend or flex any of your joints. When you extend or flex a joint past your brain’s comfort zone, it registers this as a threat, and sends a signal to your muscles to stiffen, preventing you from extending or flexing a joint to the point of injury. 

Of course, the reason for this is that if you were to extend or flex a joint far past its normal range of motion, this could cause serious damage to blood vessels, ligaments, nerves, and other structures around the joint. 

For example, if you “stretch” your head too far to either side, the result will look like this: 

Here’s another (less dangerous) example: 

If you put your right arm out in front of you with your palm facing the ground, and you flex your wrist back toward your body, your brain is probably comfortable with you moving your wrist about 45-degrees. Flexing your wrist past this point (or pushing it past this point with your left hand), will feel increasingly uncomfortable. 

This isn’t because the muscles and tendons in your hand are too “stiff” or “short,” but instead is because your brain is telling your muscles to contract to prevent you from moving your wrist outside of its normal, safe range of motion.

If you were to stretch your wrist consistently by pulling your right hand back toward your body with your left, your brain would gradually allow the muscles in your hand to relax and your flexibility would increase.

That’s how stretching helps you become more flexible. 

But does being more flexible actually make you fitter or healthier? 

No, at least not directly.

Stretching and being more flexible doesn’t inherently make you fitter or more athletic. 

As you just learned, some level of joint “stiffness” is normal and healthy. You want your joints stiff enough to stay in a healthy range of motion. 

If your lack of flexibility prevents you from performing certain movements, though, such as squatting to parallel, getting in the proper position to deadlift a barbell, or lock your arms when overhead pressing, stretching can improve your fitness.

There are also a few sports where your performance is heavily dependent on flexibility, and thus where stretching might be necessary. Gymnasts, swimmers, martial artists, dancers, yogis, and acrobats all need extreme flexibility, which is why most of them do some form of stretching. 

If you just want to lose fat, build muscle, get strong, and stay injury-free, though, you don’t need to stretch.

Keep in mind that most exercises also double as stretches. For example, pull-ups are a great upper back stretch, squats are a great lower-back and hip stretch, and the bench press is a great chest stretch. 

In many cases, the best stretch for improving your range of motion is whatever exercise you’re having trouble with. For example, if you have trouble squatting to parallel (the point where your hips are at the same level as your knees), you may just need to focus on squatting a little deeper in your workouts.

Summary: Stretching improves your flexibility by teaching your brain to relax your muscles, which increases your flexibility. That said, being more flexible doesn’t necessarily make you fitter, healthier, or stronger.

Stretching and Injury Prevention

benefits of stretching

The prevailing wisdom about stretching and injury prevention goes something like this: 

The more flexible you are, the less likely you are to strain a muscle or tear a tendon.

While this idea seems plausible, there’s no scientific evidence to support it.

For example, a 2008 study conducted by scientists at Amager Hospital examined whether or not a preventative exercise program that included stretching could reduce overuse knee injuries and medial tibial stress syndrome (“shin splints”). 

In this study, the researchers split 1,020 Danish soldiers undergoing three months of basic training into two groups: 

  1. The stretching group did three fifteen-minute sessions per week of five exercises focused on improving their lower body strength, flexibility, and coordination.
  2. The placebo group did five upper body strength, flexibility, and coordination exercises.

The researchers recorded how many lower-body injuries soldiers in both groups sustained throughout the course of the study. 

They found that both groups had almost the exact same risk of injury: there were 50 injuries in the stretching group, and 48 in the placebo group.

Other studies conducted by scientists at Flinders University and Bispebjerg Hospital have found the same thing: stretching doesn’t reduce your risk of getting injured. 

There’s even some evidence to suggest that stretching could increase the risk of injury. Researchers have found that stiffer muscles are generally more efficient at absorbing energy during exercise, which could reduce the risk of muscle strains or tears.

On the other hand, most studies have simply found that stretching doesn’t affect your risk of injury at all, for better or worse.

Summary: Most research shows stretching won’t reduce your risk of injury, although it probably won’t hurt, either. 

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Stretching and Performance

Stretching and performance have a complicated relationship.

On the one hand, it makes sense that “loosening up” before you train might translate into better performance. We’ve all experienced feeling “tight” and “stiff” before working out, and it seems logical that stretching would help us move more efficiently during exercise. 

And of course, this is also what we’ve been told for decades by gym teachers, coaches, and fitness gurus.

On the other hand, there’s just about no evidence stretching actually improves performance. 

Studies from the University of Western Australia, University of Milan, the University of Northampton, and McMaster University have found that stretching either doesn’t improve performance, or even decreases it. 

For example, a 2012 review study conducted by scientists at the University of Northampton found overwhelming evidence that athletes who stretch a muscle for 30 to 45 seconds don’t experience any improvement in performance.

What’s more, they also found that when athletes stretched a muscle for longer than 60 seconds, they typically experienced a significant decrease in performance. 

A clear example of this comes from a study conducted by scientists at the University of Tampa, who found that runners who stretched their calves, hamstrings, quads, hip and knee flexors, and glutes for a total of 90 seconds each were eight-percent slower on a one-mile uphill running test. A similar study also found stretching can reduce the pace at which runners start a race.

Other research shows stretching can reduce sprint speed, jumping performance, strength, power and force output, and perhaps even muscle growth.

So . . . we should write it off sharpish, yeah?

Not so fast—the devil is in the detail.

The majority of studies that show stretching has a detrimental effect on performance have participants . . . 

  • Holding stretches for 60 to 90 or more seconds
  • Pushing the limits of their range of motion (the kind of stretching that hurts)
  • Stretching immediately before working out 

This isn’t how most people stretch in the real world. 

Instead, most recreational athletes might gently stretch a muscle for 20 or 30 seconds, and it’s usually part of a warm-up routine that takes place at least a few minutes before they work out.

They want to loosen up, sure, but they aren’t trying to test the upper limits of their muscles’ or tendons’ elasticity.

What would the results of these studies look like if they used more realistic stretching protocols? 

Well, a team of scientists at the Federal Institute of Sudeste of Minas Gerais sought to answer that question in a recent study.

The researchers had three groups of untrained men perform four sets of seated hamstring curls to failure, using a weight that allowed them to get 8 to 12 reps, with 90-second rest intervals, 2 days per week, after either no stretching, pre-exercise static stretching, or pre-exercise dynamic stretching for eight weeks.

Static stretching refers to stretches that involve holding stretched positions for various lengths of time.

Dynamic stretching refers to movements that repeatedly put muscles through their expected ranges of motion, such as air squats, leg kicks, side lunges, arm circles, and so forth.

The stretches were all performed for 20 seconds, and to the point of mild-discomfort, which is similar to what most people limbering up for a weightlifting session might do.

The results?

All three groups increased their strength, muscle thickness, and total training volume to similar degrees. 

All in all, intense, prolonged static stretching immediately before training seems to reduce performance, moderate-intensity, brief static and dynamic stretching seems to either be neutral or beneficial.

Thus, if you like stretching before you work out, then stretch—just make sure your stretching isn’t too intense or protracted.

At this point you may be wondering, what about stretching away from your workouts? 

That is, if you train in the evening, would stretching in the morning have any negative effect on your performance? 

Could it even have some benefits? 

Quite possibly.

In a systematic review study conducted by scientists at the Federal University of Rio Grande do Sul, researchers looked at 28 studies to see what effect chronic stretching had on muscle performance (a catch-all term for a variety of disciplines including jumping, sprinting, and strength training).

Of the 28 studies reviewed, 14 showed stretching had beneficial effects on muscle performance, while 14 found stretching to have no effect. Crucially, however, none showed any decrease in muscle performance.

Although it’s not clear why stretching would improve muscle performance, researchers think it may be because it decreases the stiffness of muscle-tendon units (MTU)—the name for the tendon, the connective tissue, and the muscles as a group. They also think it may improve the ability of muscles to add new sarcomeres to muscle fibers, which are the tough strings of protein that lead to the generation of new muscle tissue

Scientists think that more flexible MTUs may be more efficient at storing energy during eccentric movement (such as the descent during a squat), and that energy can be released during concentric movement (such as the ascent during a squat). Thus, theoretically, more flexible MTUs could boost performance. 

This could be particularly helpful for us weightlifters during exercises like the squat and bench press, where the eccentric portion of the lift precedes the concentric portion, though it wouldn’t be as helpful in exercises where the reverse is true, like the deadlift.

Time will tell how these theories pan out, but here’s what we do know: 

As long as you don’t intensely stretch a muscle for more than around 30 to 45 seconds, and you don’t stretch right before a workout, stretching may have some performance benefits and likely has no downsides.

Summary: Intense, prolonged (60+ seconds) stretching immediately before exercise decreases performance. Light, brief (<45 seconds) stretching, done at least several minutes before exercise, probably doesn’t hurt and may improve performance.

Stretching and Recovery

statistics on the benefits of stretching

Until fairly recently, tastemakers in the fitness world extolled the rejuvenative benefits of a good cool-down routine. 

Warm-ups were a given, but slowly bringing your body back to some semblance of normality after a hard workout with a mix of low-intensity movement and some static stretching was also held up as an important part of the puzzle. If you wanted to kick your recovery up a notch, you could do some deep stretching a few hours post-exercise, too, especially if you were feeling sore.

This, we were told, would “flush” metabolic byproducts out of our system that normally interfere with our recovery, and would relax our muscles, helping them to recover faster.

Of course, all of this was before good ol’ science came along and spoiled the party.

Research reviews conducted by scientists at the The George Institute for Global Health, SMBD-Jewish General Hospital, Montreal, and the University of Sydney have since found that stretching, whether before or after exercise, has no effect on muscle soreness or recovery. 

Studies have also shown that metabolic byproducts associated with fatigue are cleared soon after you workout, and that stretching does nothing to help the process, nor does it have any effect on the blood chemicals that are generally associated with fatigue.

What’s more, there’s some evidence stretching may contribute to muscle soreness, especially if you’re not used to doing it or if you stretch for too long.

Does this mean stretching is worthless for recovery? 

Well, the answer would seem like a resounding yes, if not for a 2018 study conducted by the University of Toronto that used a more realistic stretching protocol than the ones employed in most previous research.

The researchers took 30 recreationally active, resistance-trained young men, and split them into three groups: 

  1. No-stretching
  2. Low-intensity stretching
  3. High-intensity stretching

The participants followed a brutal eccentric leg workout protocol consisting of six sets of ten maximal eccentric reps with two-minute rest intervals between sets. After exercising, participants were asked to rate their perceived soreness on a scale of zero to ten as the researchers poked and prodded at their quads.

Before being sent home, participants in the stretching groups were given stretches to perform on their own before they went to sleep for the three nights that followed. The stretching routine included one quad stretch, one hip flexor stretch, and one hamstring stretch.

The low-intensity group was instructed to stretch at an intensity of three or four out of ten (or until they felt a warm, gentle feeling), and the high-intensity group was instructed to stretch at an intensity of seven or eight out of ten (or until they felt discomfort or slight pain). Each stretch was held for 30-seconds and performed three times on each leg once per day.

At the end of the study, the only statistically significant difference between the groups was that muscle strength recovered faster in the low-intensity stretching group than in the other groups. 

Although not statistically significant, muscle soreness also tended to disappear faster among people doing low-intensity stretching than in the other two groups.

Once again, it seems that how intensely you stretch significantly affects the benefits. 

While previous research showed how medium-intensity stretching did nothing to aid recovery, this study found that low-intensity stretching may make post-workout soreness disappear faster.

If you think about it, this makes sense, too, 

Intense static stretching places muscles under a lot of tension, which can cause some muscle damage and thus soreness. Low-intensity stretching, though, causes little to no muscle damage, and thus probably doesn’t cause muscle soreness

Researchers aren’t sure why it would reduce muscle soreness, either, but based on these study results, it may.

Summary: Intense stretches held for 60 seconds or more don’t aid recovery and may increase muscle soreness, but there is some evidence that low-intensity, short-duration stretching may help hasten muscle recovery and reduce muscle soreness.

Stretching and Muscle Growth

For years bodybuilders have said that stretching during rest periods at the gym, or after a workout, increases muscle growth.

Is this true? 

Based on what you now know about stretching and performance, you’d think the answer would be a clear no. If getting stronger is the best way to build muscle, and stretching immediately before your workouts decreases strength, then it would seem like stretching should hurt muscle growth, not help.

Strangely, though, some research shows the bros may have been right all along—stretching may help boost muscle growth. 

Evidence for this idea comes from a study conducted by scientists at Nove de Julho University, who split twenty-nine untrained men into two groups:

1. A stretching group, which stretched the main muscle groups they were training between sets.

For example, if they were doing sets of bench press, they’d stretch their pecs between sets. If they were doing rows, they’d stretch their lats, and so on. They stretched each muscle for about 30 seconds, at an intensity of just below pain or discomfort.

2. A no-stretching group, which rested between sets.

Both groups followed the same full-body training program, involving the bench press, seated row, seated machine dip, bicep curl, hamstring curl, and leg extension.

The researchers measured the participants’ bench press and knee extension one-rep max (1RM), and muscle thicknesses for the biceps, triceps, rectus femoris, and vastus lateralis before and after the study.

After eight weeks, the only statistically significant difference between the two groups was that the stretching group experienced an increase in vastus lateralis thickness, whereas the no-stretching group didn’t. 

That said, even though the results weren’t statistically significant, there was a clear trend for greater muscle growth in the stretching group. Specifically, they gained more muscle thickness in the biceps, triceps, and rectus femoris than the no-stretching group.

If you sum up the difference across all four muscle groups, the stretching group increased their muscle thickness by 9.4 mm and the no-stretching group increased it by 6.2 mm, a 50 percent difference. 

So, does this mean stretching between sets will help you build more muscle? 

Not necessarily. 

These results still weren’t that impressive and haven’t been replicated by other researchers, but at the very least, they show stretching is unlikely to impede muscle growth. 

It’s also worth noting that intense, prolonged stretching immediately before lifting weights can reduce how many reps you can do in your workouts, which can hinder muscle growth over time. 

So, if you do decide to stretch before or during your workouts, just make sure you don’t stretch too intensely (a 7 out of 10 on a scale of 1 to 10 would probably be a good maximum intensity), or hold your stretches for too long (30 seconds is probably a good maximum duration).

Summary: Intense, prolonged stretching immediately before or during your weightlifting workouts may interfere with your performance, although at least one study has shown that moderate, brief stretching between sets could increase muscle growth by a small margin.

The Right Way to Include Stretching in Your Training

mental benefits of stretching

There are plenty of reasons why stretching has earned a bad rap: it doesn’t prevent injury, it can decrease performance, it can inhibit recovery, and it can interfere with muscle growth.

That said, most of the downsides of stretching can be avoided by not stretching too intensely, not holding a stretch for too long, and not stretching right before or after workouts. 

Let’s take a moment to look at the best ways to stretch for different goals.

How to Stretch If You Want to Improve Flexibility

Some level of muscle stiffness is normal, even healthy.

A lack of flexibility only becomes a problem if it prevents you from doing an exercise you’d like to be able to do.

For example, if you can’t reach proper depth on a squat, push a barbell overhead without shoulder pain, or keep your back from rounding during the deadlift, you may want to work on improving the flexibility of the muscles that are holding you back. 

Prolonged stretching will definitely improve your flexibility, but it will also hinder your performance in the gym if you do it immediately before your workouts. Some research suggests that these negative effects only last about 10 minutes, though other studies have found the effects last about an hour.

With this in mind, it makes sense to stretch after your workout, or better still, several hours away from your workouts. For a lot of people, nighttime or early morning is convenient, since stretching is a nice way to start your day or wind down before sleep.

Also, avoid prolonged or intense stretching for muscles you’ve just trained in the gym. Post-workout is not the time to be working on the flexibility of a muscle that is already beaten up after a hard weightlifting session.

The American College of Sports Medicine recommends stretching each muscle two to three times per week for between 10 and 30 seconds per stretch to the point of slight discomfort, accumulating 60 total seconds per muscle. These are pretty sound recommendations. 

If you’re interested in learning more about how to stretch different muscles, check out these articles and podcasts: 

The Definitive Guide to Mobility Exercises: Improve Flexibility, Function, and Strength

How to Improve Flexibility and Mobility for Squatting 

How to Improve Shoulder Flexibility and Mobility 

Justin Andrews on Quick and Easy Ways to Improve Whole-Body Mobility

My Daily 10-Minute Yoga Routine for Better and Safer Workouts

How to Stretch If You Want to Loosen Up for a Workout

Stretching is synonymous with warming-up despite the damaging effect on performance it can have.

To prevent stretching from interfering with your performance in the gym, keep your pre-exercise stretching short and at a low intensity.

For example, if you’re warming up for leg day, run through a quick stretching routine that incorporates your quads, glutes, hamstrings, hip flexors, groin, calves, and ankles. Just be sure to hold your stretches for a maximum of 20 seconds, and only to the point of very mild discomfort—around a 5 or 6 on a scale of 1 to 10.

If you want to learn more about how to properly warm-up for your workouts, read this article: 

The Best Way to Warm Up For Your Workouts

How to Stretch If You Want to Improve Recovery

When it comes to stretching for recovery, long-duration, intense stretching should be avoided. As you learned a moment ago, stretching in this way may actually increase muscle soreness and delay recovery.

Instead, in the first 24 to 48 hours after training, gently stretch the trained muscles for a maximum of 30 seconds, up to an intensity of 3 or 4 out of 10. 

Don’t expect miracles, though—the results are likely to be negligible at best. It might help, or it might do nothing, but it’s unlikely to hurt if you follow these guidelines. 

If you want to learn more about methods to improve your workout recovery, read this article: 

The Definitive Guide to Muscle Recovery

How to Stretch If You Want to Aid Muscle Growth

First of all, it’s worth remembering there’s very little evidence this works: just one study . . . with only about 30 participants . . . which found a very, very small increase in muscle growth . . . in one muscle.

That said, it’s unlikely to hurt and might help, and at the very least it’ll give you something to do between sets. 

So, if you want to give inter-set stretching a try, stretch the main muscles that you’re training during the rest periods between your heavy sets. Keep the stretches around the 30-second mark, and only stretch to just below the point of discomfort—probably to around a five or six on a scale from 1 to 10.

If you want to learn more about “advanced” methods for improving muscle growth, check out these articles and podcasts: 

Does Blood Flow Restriction (Occlusion) Training Really Work?

Should You Use Supersets to Build Muscle Faster? What 18 Studies Say

Chris Barakat on Advanced Bodybuilding Techniques for Faster Muscle Gain

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The Bottom Line On Stretching 

When it comes to stretching, the minutiae matters.

Adopting a one-size-fits-all approach won’t help your progress, and may even make reaching your goals more difficult.

First, understand that stretching doesn’t inherently improve your health or fitness. It’s not an essential aspect of proper workout programming, and it’s not without downsides. 

Second, you need to decide why you want to stretch. Do you want to improve your flexibility? Prevent injuries? Improve performance or recovery? 

The best stretching strategy for one goal may not be the best for another, and in some cases, stretching may even detract from your goals. 

If you want to improve your flexibility, stretch each muscle 2 to 3 times per week for between 10 and 30 seconds per stretch, to the point of slight discomfort. 

If you want to loosen up for a workout, hold each stretch for a maximum of 20 seconds and only to the point of mild discomfort—around a 5 or 6 on a scale of 1 to 10.

If you want to improve recovery, gently stretch trained muscles for a maximum of 30 seconds, up to an intensity of 3 or 4 out of 10.

If you want to increase muscle growth, stretch the main muscles you’re training during the rest periods between your heavy sets, keeping the stretches to around 30 seconds, and only to just below the point of discomfort—about 5 or 6 on a scale from 1 to 10.

Assuming you follow the recommendation laid out in this article, you should be able to get all the benefits of regular stretching without any adverse effects.

What do you think about stretching? Have anything else to share? Let me know in the comments below!

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