Everything You Know About Stretching Is Wrong
We stretch for a variety of reasons: because it feels good, because it’s part of our pre-workout routine, because the muscles are stiff and we think stretching will fix it. But much of what we know about stretching – and therefore how we use it – is based on wishful thinking and outdated science. We’re stretching for the wrong reasons.
Christie Aschwanden recently wrote about why she stopped stretching before exercising – mainly because science doesn’t support the idea that it prevents injury. I haven’t done stretching in years either, unless I had a specific area of mobility that I wanted to work on (for example, lying on a foam roller to work the arch for the bench press). When I played roller derby, the team would drop to the floor at one end of the rink as we systematically stretched every muscle in our body. For a while, I was constantly getting pulls in the groin – the tension of the muscles in the inner thighs – until one day I wondered what would happen if I did not stretch those muscles before training. The repetitive nagging trauma stopped almost immediately, and based on this experience, I completely stopped stretching.
That was ten years ago and I never started again. But most of my teammates did stretch out, convinced that it would help them avoid injury. Plus it was part of everyday life.
Stretching is rooted in tradition and myth. Like targeting fat , it gives catchy headlines and snappy advice in the locker room, but science doesn’t really validate the assumptions athletes make.
In many cases, stretching does the opposite of what it is being promoted for. You already know that this does not prevent injury . It also does not treat muscle soreness; In fact, aggressive stretching can cause muscle soreness. And pre-workout stretching not only does not prepare you for training, but also deprives you of strength. Here’s the truth behind some of these persistent myths:
Stretching does not heal muscle pain
I often hear athletes ask each other, “Do you know how to stretch this muscle well?” It is said that before or during exercise, this is almost always because the person has muscle soreness and is looking for a way to fix it. It almost makes sense: stretch the sore muscle well. Or at least you seem to be doing something.
But stretching does not provide long-term pain relief (and does not prevent soreness) . The sad truth about muscle soreness is that there really is nothing you can do to get rid of it; muscle fibers are damaged and take time to heal.
In fact, stretching itself can damage muscle fibers – you are simply tearing them apart, stretching, not contracting. If you want to stop feeling soreness, aggressive stretching is the last thing you need to do.
Since stretching a muscle is tension – similar to soreness, people often have the same reaction when they want to stretch a stretched muscle. Here the idea is even worse: the stretched muscles must heal again, and the stretching sabotages this process.
Stretching robs you of strength in the short term (but good for you in the long term)
If you stretch as part of a pre-workout warm-up when it comes time to lift that weight or make a sudden movement, you will be weaker than if you weren’t stretching . The effect lasts a minute, or perhaps half an hour.
Most of the studies that tested this idea used simple, measurable exercises like the jump test. If you jump after stretching, you will not be able to jump as high as if you did the jump test without first stretching. In studies, people typically stretched aggressively for several minutes. It’s hard to say exactly how this applies to training in the real world: a review published in the European Journal of Applied Physiology found that short, gentle stretches sometimes seem to improve performance .
This is partly why ” dynamic stretching ” is popular these days. Instead of working on one stretch for 30 seconds or more, you guide your body through an exaggerated version of your normal range of motion. Maybe it’s jogging with high knees and butts, or crawling on the ground like Spider-Man. But calling it stretching might mean the wrong focus: perhaps spending the same time doing regular cardio or strength training will have the same effect. After all, the key features of a warm-up are to get the blood to flow, literally warm up the muscle tissue, and get your cells to activate their calorie-burning mechanism (it takes a few minutes).
And yet there is a paradox: people who stretch regularly end up being stronger than those who don’t. They temporarily decrease their strength, but build it up in the long run. Why? Probably due to the muscle damage we talked about earlier. If both weightlifting and stretching can cause muscle damage, they should force the muscles to regenerate harder than they did in the beginning. Stretching does cause hypertrophy – muscle growth – and that seems to explain why people who stretch get stronger over time.
Stretching doesn’t make your muscles bigger
Stretch a muscle and it will get longer, right? This is how we assume stretching works, but it turns out that it may not be true – which means that many ideas about why we should stretch are in question.
One of the leading theories is that stretching does not lengthen muscles; it just changes your perception of pain , so when the muscles stretch, you don’t mind. This may explain why stretching doesn’t protect against injury: you haven’t changed the way your joints or muscles move.
Muscles can be lengthened, but not only by stretching. If you contract a muscle during lengthening (eccentric exercise), this seems to be the key to lengthening the muscle . It makes sense that some of the most flexible athletes – such as ballerinas and yogis – do this type of exercise hundreds of times per workout.
Instead of stretching, it is more fashionable these days to talk about “mobility work”, which can include eccentric work or dynamic stretching in addition to or instead of static stretching. For example, if your calves are too tight to allow you to squat as deep as you want, ankle mobility work can help you squat better.
When to stretch (and when not)
Now that we know the truth about stretching, another set of stretching recipes emerges:
- If you need strength in your workout (because you’re lifting weights, or running, or doing sports that require sudden bursts of strength), skip static stretches beforehand. Dynamic stretches are a great replacement, but you can experiment by skipping the stretch entirely.
- If you enjoy stretching after a workout or over the weekend, it probably won’t help or hurt. You can increase your flexibility and possibly your strength. (You can also stretch before training if you don’t care how your strength is reflected during training.)
- If your muscle is sore or stretched, stop stretching or do it very carefully. Small, light cardio, such as walking, will provide similar temporary pain relief without damaging more muscle fibers.
- Stretching will help if you want to develop flexibility in the long term, but consider using multiple types of mobility, not just static stretching.
You can look a bit strange if you are the only person in the gym, which does not stretch before exercise and prefers to roll with foam sore muscles, but do not stretch it, but your muscles will thank you for it.
This article was first published in 2015 and was updated in September 2020 with a personal anecdote and more recent information.