Howdy,
Lets go straight to the topic… The thing we know is that it’s not reasonable to do static stretching (classic protocol) before explossive activities (at least), because it doesn’t make sense to relax muscle before power work (plus some studies say that stretching before competition and training weakens muscles and increases risk of injury – not actually decrease it). To do it or not to do it after training or as a separate session, depends on a few factors… Lets see what science and common sense say in general.
But before we start answering these questions, the idea that stretching weakens muscle has definitelly caught my attention. What’s the deal? In one research, elite college sprinters were timed in 20 meter sprints, with and without prior multiple 30-second stretches of their leg muscles. Both active and passive stretching slowed them down. Stretching prevents you from lifting your heaviest weights or running your fastest miles. It limits how high you can jump, and how fast you can run. Stretching weakens muscles temporarily by almost 5.5%. The longer you hold the stretch, the more strength you lose. Holding a stretch for more than 90 seconds markedly reduces strength in that muscle. Stretching reduces power: how hard you can hit a baseball or tennis ball or how fast you can swim, run or pedal. Stretching decreases the amount of energy you can store in muscles and tendons and therefore weakens you and you have less stored energy to drive you forward, so you have to slow down. When you stretch a muscle, you pull on the muscle fibers and stretch apart each fiber at the thousands of Z lines between the sarcomeres. This damage occurs only at the Z lines throughout the length of the muscle fiber, to weaken the entire muscle. On the other hand, warming up makes muscles more pliable, helps you to run faster and lift heavier, and helps to prevent injuries. I believe though, that this weakness occurs only when stretching before training (neurological factor).
Unless you are under anesthesia (where you will miraculously gain full and even excessive range of motion), your ability to stretch at any range is determined by your nervous system’s tolerance to that range. So, the nervous system is running the show (one group of researchers believe that it’s not true that if we stretch more and harder our tissue will change). Increasing flexibility may be actually more of a nervous system “hack” than a matter of changing tissue. If you do some upper body stretching, your lower will get a little more flexible. Not much, but enough to measure in a controlled test (it’s due to an increase in tolerance to stretch, and that’s all). It’s one of many clues suggesting that stretch tolerance is the secret sauce in flexibility. In other words, muscle (probably) doesn’t change (nor tendon properties), especially in response to an average stretching regimen…but our willingness to elongate it probably does. Stretching is a way of teaching the nervous system that it’s ok to stretch a little further. But it’s not easy to achieve significant stretch tolerance – it takes weeks of diligent effort, quite a bit more than mot people ever actually push themselves to achieve. Many people probably believe that they have achieved this, but it’s mostly wishful thinking, and the huge majority have only scratched the surface of their potential flexibility during brief phases of their lives.
Static stretching (SS) has no effect in reducing injuries. Neither poor quality nor higher quality studies reported any injury prevention effect. Regardless of whether stretching was of individual muscles or entire groups, there was no reduction in injury rates. Usually, advocates say that “longer” muscles are less likely to get strained. Even if stretching made muscles longer (which is doubtful in itself), and even if we knew exactly what kind of stretching to do (we don’t), and even if we had the time to stretch every significant muscle group, the benefits would still be relevant to only a small fraction of common sports injuries. An ankle sprain, for instance, or a blown knee – two of the most common of all injuries – probably have nothing to do with muscle length. Also, muscles and tendons tear when the force applied to them is greater than their inherent strength, so anything that makes a muscle stronger helps to prevent injuries. Stretching does not strengthen muscles so it does not prevent injuries such as shin splints, bone stress fractures, sprains or strains.
The evidence strongly suggests that stretching does not prevent DOMS neither (actually neither prevents nor treats DOMS, therefore it’s useless to use it for the muscular recovery standpoint). A review of 12 studies published over the last 25 years shows that stretching does not prevent DOMS. Whatever effect stretching has on inflammation on connective tissue, it does not add up to a DOMS cure. It can even make DOMS worse… Here is why? I found 2 reasons why max static stretching after highly intensive workouts/games is not good: 1) Because of micro muscle lesions (DOMS), which makes sense (but we can do around 85% of max stretch which doesn’t lead to additional micro tearing; 20-30s – 8-10 exercises of big muscle groups); 2) By holding max stretched position, muscle diameter/girth becomes thinner which logically slows an important blood content for speeding up recovery (as in the previous example, 80-85% of max tension works better). It’s up to you, but in my opinion, if I think twice, I would maybe completely avoid static stretching (whether it’s gentle or not) after intensive tr. or games because we could damage muscle fibers even more – stretching muscles that are already damaged by intense exercise delays recovery and increases risk of injury (pros are not worth the risk, it could affect each athlete differently though). So, long story short, no recovery improvements nor detrimental effects on sports performance…
There is really only one stretching benefit that seems to be clear and (almost) uncontroversial: it does actually increase flexibility. Even just plain old static stretching. For whatever it’s worth, people do seem to be more flexible when they stretch regularly for a while. Real elongation of tissue is elusive, and hard to sustain – but maybe it can be done. …What about the popular theory that muscles actually change length (“plastic deformation”)? In 10 studies that suggested plastic, permanent, or lasting deformation of connective tissue as a factor for increased muscle extensibility, non of the cited evidence was found to support this classic model of plastic deformation. Increases in muscle extensibility observed immediately after stretching and after short-term (3 to 8-week) stretching programs are due to an alteration of sensation only and not to an increase in muscle and tendon length. In other words, the feeling of longer muscle has more to do with your modified sensation of your nervous system than actual (long-term) length change of the muscle. So, increased flexibility may simply be an increased tolerance for the discomfort of excessive muscle elongation. But many pros still believe that tissues adapt their structure to stretching. One good research clearly showed that stretching increases flexibility: When subjects were stretched with the same force (torque) applied, pushed to the same level of discomfort, they could go 20% farther. So we know something changed. Was it a change in tissue? Or tolerance? The wisdom of the body has excellent reasons for strictly limiting elongation when a stretch becomes uncomfortable. But apparently we can get used to stretching – we can learn to tolerate greater elongation to some extent. This goes a long way to explaining the flexibility feats of yogis and martial artists, whose hypermobility might well be dangerously dysfunctional if it were attributable to plastic deformation. Plastic deformation simply does not occur in the most athletes, and maybe none (there are some research though, showing most gymnastic or martial art stretch programs require long term holds, in many cases at least 5 minutes each and in some situations approximating 30-60 minutes, in order to see the structural changes they are after, and specifically used with younger kids who have much easier bones and joints to deform to the stretching). You can make a muscle longer while you are stretching, but after you finish stretching, the muscle returns to its former length (not counting the previous statement). So, you only learn to tolerate more pain, and that’s it. Stretching a muscle pulls on nerve fibers in the muscle to cause pain, so you stop stretching when it hurts. When a person is given an anesthetic, he/she can stretch much further because he/she feels less pain. If muscles did remain stretched, stretching would harm you because the overstretched muscle would lose its elasticity and be much weaker. Placing animals in muscle-stretching casts for several weeks can cause the muscles to grow extra units calles sarcomeres, but muscles return to their original length soon after the cast is removed.
Many casual stretching enthusiasts actually have a hard time explaining why they are stretching. Everyone just “knows” that it’s a good thing, and they haven’t really thought about why. It’s dogma, practically a religion. Many people stretch because it simply feels good! People often feel a strong urge to stretch (it feels like they are going to “seize up” if they don’t). When people stretch hams regularly and strongly, it feels as pleasantly essential to their well-being as slipping into a hot bath – but the exact nature of the benefits are completely unclear. I don’t think it’s endorphin because litteraly anything that feels good “releases endorphins”, by definition. So mentioning endorphins is just a science-y way of saying that stretching feels good.
People who feel stiff and tight usually assume their range of motion (ROM) is limited by literally short muscles, but this is rarely the case, despite how it feels. Stiffness isn’t the same as being inflexible; they aren’t even really related. Most stiffness is a sensation, a symptom, a kind of mild pain with movement rather than an actual limitation of movement. Even hypermobile people often feel stiff! Here is one example. Stop trying to stretch away hamstring tightness and think. Maybe it’s because you’re in a bad anterior pelvic tilt and the hamstrings are just lengthened (not stiff or short). Maybe that tightness is a protective response and a result (not cause) of your back pain. Maybe the muscle is overworked because your glutes are “sleeping”… Screening is key… Sometimes, haphazardly stretching certain areas of your body that feel tight could push some people into a place where they have too much uncontrollable motion, increasing risk of injury. So, doing SS for the wrong purpose and with the wrong person however can be a bad idea. Always search for the underlying why. Treat the person, not the symptom.
Many coaches consider stretching like this: “Can you touch your toes? If you can, congratulations! If you can’t, who cares? The reality is, you only need so much flexibility to be healthy and to perform well. What about preventing injury? According to 30 years of meta-research, SS might give you 1% better injury prevention. Dynamic stretching isn’t much better. Most now agree that coaches and trainers may want to avoid using stretching as a means of injury risk prevention immediately prior to athletic activities. The truth is, you’re probably already as flexible as you need to be. Under anesthesia, an 80 year-old sedentary man is able to do the splits. So what is flexibility, really? It’s a neuromuscular state that helps limit your movement to prevent injury. Your nervous system interprets the stretch as potential injury and shuts the muscle down. In turn, this causes instability of the joints attached to the muscle thus making you more susceptible to injury before the activity even starts. Best advice: save stretching for after exercise, to relax the nervous system, and learn to move better to prevent injury.”
Lets mention one more interesting thing here. Most stretching protocols involve end range holds with some level of force application against the resistive tissues for anywhere from 10-180 seconds. For the vast majority of these protocols, they show minimal to no improvement in range of motion, force production, or acute performance variables. Phil Page did a fantastic review of existing literature back in 2012 to group stretch modality studies into static, dynamic and pre-contraction (PNF, positional isometric, PAILs/RAILs, depending on your vernacular), and found most static stretching studies showed no significant difference in range of motion compared to pre-intervention, and actually decreased force production capabilities in the muscle following the stretch. For most of these protocols, the duration of stretch is insufficient to produce any notable changes to structures like tendon pliability, joint capsule ligamental laxity, bone positioning, or muscle length in terms of sarcomeres in series or positional holds of each sarcomere relative to total stretch. What they can do is create a mild reflexive relaxation in the muscle tissue, reducing sympathetic drive (this is where recovery process could be kicked on and speeded up consequently) that could be causing the muscle to hold tension and resist a specific range of motion from being reached. However, in the long run you likely won’t see much in terms of a structural adaptation to stretching other than just reducing tension. That’s reason enough for many to use it, as well as meditative breathing and other stress reduction modalities – after training.
Some research also showed that, even in the most clinically extreme populations, very long hold SS (up to half of a day) causes only relatively small increases in mobility over other modalities. It’s definitely not possible to use extremes to apply to the averages, but this gives a really clear example of kind of the upper ends of what could be achieved in terms of time, frequency and results in a highly susceptible population. So average folks likely won’t see much benefit to structural adaptations for SS unless they hold the positions for a ridiculously long time, daily, for weeks or months on end. For clinical populations, they see better benefits, but it’s small and specific to their specific concerns. Using rehab approaches to fitness problems never goes well.
Many coaches don’t believe that SS is any more generally useful for people than it is for cats – you do it when you get up in the morning for a few seconds and then you are off to the sandbox. That feels good – it’s stimulating and enhances your body awarness, it scratches some simple physiological itch, and that’s fine and dandy. Don’t get me wrong here, if you used to do it and you see some benefits, keep doing it. But if you just talk to your teammate, please stop… In short, stretching appears to be good for… more stretching. And, of course, stretching does feel pleasant. There are some research showing though, that SS reduces edema growth and improves subjective feeling. Also, look below what John says… PS: And, yes, SS could be useful to prevent muscle contracture after injuries, if nothing else is possible.
“Holding static stretches from 30-90 seconds while maintaining optimal body alignment in other regions of the body, most notably the spine and pelvis, can stimulate a recovery response in the parasympathetic nervous system due to receptors found in the soft-tissues themselves. Follow up the tissues you addressed in your foam rolling and self-myofascial release work with static-based stretching for optimal recovery benefit. Most people will have a great amount of success with the implementation of foam rolling and stretching in the post-workout window.” – John Rusin
Even though some studies have shown that there are no positive effects on recovery, SS could actually work for speeding up recovery (probably not for all people though). I mean, it really makes sense what John says. …SS is good for your heart! “Enhanced vagal modulation” is fairly straightforward good-news science about stretching… When i say this, I mean on SS immediately after highly intensive work, whether in gym or on the court (the cooldown is the best place to do SS, and combining it with breathing makes it more effective). Doing SS as a separate session might not work when it comes to recovery (maybe only if an athlete is highly stressed all day long, in addition to some other techniques)…
Also, remember that SS does not “warm up” muscles. Holding a stretched muscle does not generate much heat and therefore does not warm up muscles. Since almost 80% of the energy used to power muscles is lost as heat, you must contract and relax muscles continuously to generate the heat necessary to raise muscle temperature. …If you decide to continue stretching even after you have read all of my reasons not to, be sure to warm up first; do not stretch “cold” muscles. If you enjoy SS, and it feels good for you, keep doing it. There is definite benefit to modulating muscle tension when needed, but in terms of improving joint range of motion (at least), there are better ways to do it. If you want to use longer hold SS to potentially alter joint mechanics or capsular stuff, be prepared to hang out there for a longer time than you’re used to. Start with 20 minute holds and see how you respond to that. If your extremities start to tingle, back off a bit so you aren’t losing circulation or stretching a nerve, but progress will be slow regardless of how aggressively you approach the stretch.
Last but not least, let’s see what widely recognized PT Adam Meakings thinks: “Static stretching is a waste of time. It takes a lot of time and effort to increase flexibility. There are far more efficient and effective ways to gain flexibility. Gains in flexibility are small and short lasting. You need to do it regularly and dedicate a lot of time for small results. Stretching doesn’t improve performance (in fact, it may even harm it). Stretching doesn’t reduce your risk of injury for most things that involve strength, power, speed, or endurance. Stretching has no other significant health benefits except maybe some small psychological effects for those that ‘truly’ enjoy it. Stretching is often only done by many due to clinicians recommending it, normally due to ignorance and misuderstanding in thinking it helps. Stretching tries to scratch an itch that it just can’t reach, because ‘stiffness’ sensations are often caused by weakness, fatigue, or fear. Instead of stretching, use your time to move or strengthen things that feel stiff!”
Robert Palka thinks very similarly: “if you like it, have it. If you don’t, skip it. Not much special about it. Boring AF imo. Performance? Pfft. Injury reduction? Lol. Cool down? Not if you don’t like it. Warm up? Time could be used better. Even dancers are abandoning static stretching as it doesn’t have the benefits they need.”
PRACTICAL RECOMMENDATIONS
- it’s not reasonable to do static stretching (classic protocol) before explossive activities (at least), because it doesn’t make sense to relax muscle before power work (plus some studies say that stretching before competition and training weakens muscles and increases risk of injury – not actually decrease it). More on this below.
- SS does actually increase flexibility. One group of researchers believe that it’s not true that if we stretch more and harder our tissue will change. Increasing flexibility may be actually more of a nervous system “hack” than a matter of changing tissue. If you do some upper body stretching, your lower will get a little more flexible. Not much, but enough to measure in a controlled test (it’s due to an increase in tolerance to stretch, and that’s all). Muscle (probably) doesn’t change (nor tendon properties), especially in response to an average stretching regimen… Plastic deformation simply does not occur in the most athletes, and maybe none (there are some research though, showing most gymnastic or martial art stretch programs require long term holds, in many cases at least 5 minutes each and in some situations approximating 30-60 minutes, in order to see the structural changes they are after, and specifically used with younger kids who have much easier bones and joints to deform to the stretching). If you want to use longer hold SS to potentially alter joint mechanics or capsular stuff, be prepared to hang out there for a longer time than you’re used to. Start with 20 minute holds and see how you respond to that. If your extremities start to tingle, back off a bit so you aren’t losing circulation or stretching a nerve (at least), but progress will be slow regardless of how aggressively you approach the stretch. You can make a muscle longer while you are stretching, but after you finish stretching, the muscle returns to its former length (and no other adaptation but neural, long-term), in most (normal) protocols. So average folks likely won’t see much benefit to structural adaptations for SS unless they hold the positions for a ridiculously long time, daily, for weeks or months on end. As we said, acute SS doesn’t cause changes in ROM all that much (10 mins later you no longer have more extensibility you had right after stretching the specific muscle). But, chronic SS does improve joint ROM (tissue extensibility), it does cause chronic changes (neural adaptations in most cases). …In some people, it seems that SS may increase muscle force as well…
- Some research though support the notion that muscle fascicle length can change in the shorter run, and changes most with eccentric loading. This is why we suggest using eccentrics in a mobility or “stretching” program. It works!
- Static stretching has no effect in reducing injuries. Regardless of whether stretching was of individual muscles or entire groups, there was no significant reduction in injury rates in most studies (muscles and tendons tear when the force applied to them is greater than their inherent strength), so, long story short, anything that makes a muscle stronger helps to prevent injuries.
- The evidence strongly suggests that stretching does not prevent DOMS neither (actually neither prevents nor treats DOMS, therefore it’s useless to use it for the muscular recovery standpoint). It can even make DOMS worse… Here is why? I found 2 reasons why max static stretching after highly intensive workouts/games is not good: 1) Because of micro muscle lesions (DOMS), which makes sense (but we can do around 85% of max stretch which doesn’t lead to additional micro tearing; 20-30s – 8-10 exercises of big muscle groups); 2) By holding max stretched position, muscle diameter/girth becomes thinner which logically slows an important blood content for speeding up recovery short-term (as in the previous example, 80-85% of max tension works better). It’s up to you, but in my opinion, if I think twice, I would maybe completely avoid static stretching (whether it’s gentle or not) after INTENSIVE tr. or games because we could damage muscle fibers even more – stretching muscles that are already damaged by intense exercise delays recovery and increases risk of injury (pros are not worth the risk, it could affect each athlete differently though). So, long story short, no recovery improvements nor detrimental effects on sports performance… Below, you can see some major points…
- People who feel stiff and tight usually assume their range of motion (ROM) is limited by literally short muscles, but this is rarely the case, despite how it feels. Here is one example: Stop trying to stretch away hamstring tightness and think. Maybe it’s because you’re in a bad anterior pelvic tilt and the hamstrings are just lengthened (not stiff or short). Maybe that tightness is a protective response and a result (not cause) of your back pain (the body has some stability issues somewhere around in most cases). Maybe the muscle is overworked because your glutes are “sleeping”… Screening is key… Sometimes, haphazardly stretching certain areas of your body that feel tight could push some people into a place where they have too much uncontrollable motion, increasing risk of injury. So, doing SS for the wrong purpose and with the wrong person however can be a bad idea. Always search for the underlying why. Treat the person, not the symptom. PS: The truth is, you’re probably already as flexible as you need to be. Save stretching for after exercise, to relax the nervous system, and learn to move better to prevent injury.
- What they can do is create a mild reflexive relaxation in the muscle tissue, reducing sympathetic drive (this is where recovery process could be kicked on and speeded up consequently). Holding static stretches from 30-90 seconds while maintaining optimal body alignment in other regions of the body, most notably the spine and pelvis, can stimulate a recovery response in the parasympathetic nervous system due to receptors found in the soft-tissues themselves. Follow up the tissues you addressed in your foam rolling and self-myofascial release work with static-based stretching for optimal recovery benefit (John R.). Most people will have a great amount of success with the implementation of foam rolling and stretching in the post-workout window. PS: 30 second holds are plenty for most people, and can provide “all” the benefits.
- Don’t get me wrong here, if you used to do it and you see some benefits, keep doing it. Stretching does feel pleasant. There are some research showing that SS reduces edema growth and improves subjective feeling. And, yes, SS could be useful to prevent muscle contracture after injuries, if nothing else is possible. Even though some studies have shown that there are no positive effects on recovery, SS could actually work for speeding up recovery – as we said before (probably not for all people though). …SS is good for your heart! “Enhanced vagal modulation” is fairly straightforward good-news science about stretching… When i say this, I mean on SS immediately after highly intensive work, whether in gym or on the court (the cooldown is the best place to do SS, and combining it with breathing makes it more effective). Doing SS as a separate session might not work when it comes to recovery (maybe only if an athlete is highly stressed all day long, in addition to some other techniques)… There are some studies though, that shows benefits of SS if done away from training (not super intensive SS hours before training, or at night hours after a session, or tomorrow morning…). Most of the studies that looked prolonged SS interventions on muscular performance, showed either neutral or positive effect on muscular performance (so don’t get mad if your athlete wants to do some light SS again – hours away from training).
- If you do SS before exercise (sometimes it can be useful for specific areas after foam rolling – if short…), don’t do it very intensively because it could decrease velocity, force output, power output… Also, one study showed that, if you stretch quads super hard/intensively right before each set of leg press, you will see decrese in hypertrophy from that as well, but light sets of stretching between exercises (4 out of 10 on a pain scale, in a study), may actually increase hypertrophy a little bit. Also, long duration stretch (1-2 mins per muscle group), before training reduces power capabilities out of that muscle after (it doesn’t need to be super intensive – duration also has negative effects).
- Also, remember that SS does not “warm up” muscles. If you decide to continue stretching after you have read all of my reasons not to, be sure to warm up first; do not stretch “cold” muscles. If you enjoy SS, and it feels good for you, keep doing it. Mentioning the 2 most common reasons, there is definite benefit to modulating muscle tension when needed, but in terms of improving joint range of motion (at least) in a functional way, there are better ways to do it. And, if you do it, whenever you do – do some light and not too long stretching (of course, if you’re not a rhythmic gymnast, or similar)!
For the love of movement,
Luka