Stretching is synonymous within the health, fitness, sporting and rehabilitation world for being a panacea. Flexibility, one of the pillars of fitness, is closely linked to stretching. It is taught from a young age that stretching can prevent injury, reduce pain and make us better athletes. But how does this ingrained belief stack up against the evidence? Does it help? Should we be doing it? Are there better ways to prevent or recover from injuries? What are the common misunderstandings about stretching?
Over the next series of blogs, we will look at the evidence (or lack of) around stretching, the common misunderstandings, and what we should be doing instead. This blog is not designed to completely denigrate stretching rather to bring more awareness and understanding as to what stretching is, what it can and what it can’t do. In doing so it can make your exercise routines more efficient and possibly may even make you a better athlete.
In this series we will look at the following topics:
- What is stretching?
- Reasons why we believe stretching is good for us
- Stretching and the warm up
- Stretching and post exercise soreness
- Stretching and injury prevention
- Stretching and rehabilitation
- Stretching and athletic performance
- Stretching and flexibility
- Does stretching convey any other health benefits?
- Should we still stretch?
What Is Stretching?
Before we look at the evidence around stretching we need to understand what stretching is.
Stretching is commonly linked to flexibility and range of motion. Flexibility refers to the intrinsic properties of body tissues that determine maximal joint range of motion without causing injury. We stretch to improve flexibility and in doing so we believe it improves our overall physical fitness. Range of motion (ROM) refers to the distance and direction a joint can move between the flexed position and the extended position. The better the flexibility the better the ROM, within the confines of the joints maximal limitations.
Stretching can be broadly separated into static stretching – holding a muscle in an elongated position for a sustained period of time and dynamic stretching – which are stretches that are performed with movement. In other words, the individual uses a swinging or bouncing movement to extend their range of motion and flexibility. It is possible to argue though that this form of “stretching” is more akin to movement exercise; for a stretch to be a stretch, there needs to be a significant amount of tension held for at least several seconds, which dynamic stretching does not do.
Reasons Why We Believe Stretching Is Important
As previously mentioned, stretching is something that has become so ingrained into us to the point that it is considered sacrilegious not to stretch. Most people, when asked, struggle to explain why they stretch or understand what stretching is doing (or not doing) to the body. We blindly follow the dogma that we need to stretch to prevent injury or that it is helping us recover from an injury, without being able to explain how or why.
I have seen countless times people stretching their upper traps due to neck pain and have been doing it for many years but with little to no improvement in their pain. Why? Likely because they have been told to do it and secondly it gives them a few seconds of pain relief, even though it will quickly return. If it only provides temporary pain relief does it deserve this revered status as a pain reliever. Health professionals also have to take a fair share of the blame as stretches are commonly given as a form of a rehab and explained as something that will solve their issues, thus reinforcing the utility of stretching.
The usual reasons people but forward as to why they stretch are:
- Warm up and injury prevention
- Prevention and treatment of muscle soreness
- Treatment of sports injuries and chronic pain
- Athletic performance
There is now plentiful research that the average stretching routine people do in the gym or before a run does not achieve what they have set out to, and is a waste of time. We will look at each of the above points and explain why stretching does not achieve what we think it does when held up against the light of evidence that we currently have available.
Stretching And The Warm Up
What is the purpose of a warm up? It is to prepare the body for the activity that we are about to perform. It was long thought that a good bout of stretching was a key tenet of this principle. As an avid runner the most common thing I see before a race is people static stretching. This is done in the belief that it is metabolically warming up the muscles and will prevent injury (we look at this later) and possibly improve their performance. Evidence suggests however that stretching conveys no benefit to a persons warm up. It may in fact cause harm and reduce your athletic potential.
If we are to warm up, by which I mean the body is neurologically co-ordinated and responsive, then the goal we want to achieve is to ready ourselves for that specific activity. Therefore, a much better way to warm the body up is to perform the activity that we are going to do but at a much lighter intensity. If we are about to do a 10km race then our warm up should be a light jog, if we are about to enter a swimming race then our warm up should consist of swimming lengths at a slower intensity.
A warm up does lower the chance of injury as evidence has shown. Stretching however, plays no role in this. Warm up programs like the Fifa11+, which does not include stretching, have been widely analysed and proven to reduce injury risk. Stretching can stimulate the muscles in a minimal way but not productively enough to increase athletic performance.
Stretching And Post Exercise Soreness
We have all woken up the next day following a particularly strenuous work out routine and felt that deep painful ache in the muscles. This is what is known as DOMS (delayed onset of muscle soreness) and unfortunately there is no getting around it.
It was believed that stretching after exercise was helpful in relieving DOMS. Evidence has proven time and again that nothing, stretching included, can reduce or stop DOMS. Lund et al found concluded “that passive stretching did not have any significant influence on increased plasma-CK, muscle pain, muscle strength and the PCr/P(i) ratio, indicating that passive stretching after eccentric exercise cannot prevent secondary pathological alterations.”
The fact is there is no getting around DOMS, but should we be trying to get rid of it in the first place? Feeling DOMS suggests that you have done a particularly intense workout or you may be new to a workout. You will generally find that as you continue with a particular exercise routine, the amount of DOMS you get reduces. Your body adapts to the demands placed on it , getting stronger and therefore more able to cope. Additionally, it is likely that DOMS is a protective mechanism by the body to prevent injury. The pain and soreness felt deters you from doing another intense workout before the body has fully recovered.
Stretching And Injury Prevention
The usual argument put forward is that by stretching the muscles you are elongating them and therefore reducing the chance of a muscle strain. This concept however has no basis in fact if one truly understands what happens when somebody stretches a muscle. It also misses the point that even if stretching did elongate the muscle (which it likely doesn’t) we also have no idea how to stretch a muscle properly or what is the optimal length of time to stretch a muscle.
There is an abundance of evidence out there pointing to the fact that stretching reduces the chance of injury. As Sands suggests “the commonly accepted idea that increased ROM and stretching prior to activity prevents injuries has been challenged and found to be on the shakiest of scientific foundations, or to come from such a paucity of data that no reasonable conclusions can be drawn” Furthermore, a study on runners who either did a stretching routine or who did not found “ no statistically significant difference in injury risk between the pre-run stretching and non-stretching groups.”
Preventing injuries in sport is multifactorial and depends on a number of variables which is another topic in itself so won’t be covered here. Briefly, one needs to look at appropriate training routines, sleep, rest periods and appropriate warm up routines in helping to prevent injuries.
Stretching And Athletic Performance
Stretching unequivocally has not shown to improve athletic performance. Yet we still see coaches and athletes performing a set of stretches before events. This is not to cast blame or chastise, change takes time. It is happening but slowly. That 5 min stretch routine you do at the start at a running event is not going to save you from injury and it most certainly isn’t going to make you run quicker.
In fact, in some instances stretching has shown to have a detrimental effect on athletic performance, sprinting for example. Bizarrely this is also where musculo-tendon stiffness is actually better for you. As Beardsley explains ‘essentially, the ability of the object to absorb elastic strain energy is proportional to its stiffness. Greater stiffness of the hamstrings muscle-tendon unit therefore leads to superior absorption of elastic strain energy in the swing phase of sprinting, which will permit faster running speeds. So to all those people who believe that the springier you are the more effective your performance will be may want to reconsider their position. One aspect of fitness that can and does improve athletic performance is strengthening and needs to be incorporated into your routine.
Stretching And Rehabilitation
Stretching exercises were considered an integral part of the rehabilitation process. Fortunately, with new evidence made available, stretching is seen as a less useful tool to help patients recover. However, it is still extremely common to see patients who have just been given stretching exercises for muscle strains or for conditions that are not muscle related.
In this area I am not going to completely denigrate stretching as in some specific situations they can be potentially useful. Post-operatively they can be used to help increase ROM in the shoulder or the knee, but even when giving these exercises I don’t believe I am stretching the muscle rather improving the joint mobility.
One of the biggest misconceptions that I see is about “tightness” or “stiffness.” Both these terms are subjective symptoms or experiences much like pain. As such they can only be measured subjectively and not used as a reliable outcome measure. A health care professional telling you you are “tight” is a fairly meaningless statement. At any rate stiffness rarely results in a lack of ROM, and most people’s feeling of stiffness comes on well before they have reached the end of the motion. The stiffness felt at joints also rarely has anything to do with muscles or tendons and more about a neurologically imposed inhibition to protect the joint from further injury. Usually, though stretching exercises are prescribed to help with this “tightness”, there is likely no issue with the person’s flexibility. These exercises do provide some mild temporary pain relief, but the important word here is temporary. Usually the tight feeling comes back fairly quickly. I would best describe stretching as scratching a mosquito bite; it feels amazing but does very little for healing.
Compounded to this, terminology used in the healthcare industry has created the idea that areas of the body are always tight. This is most acutely characterised by upper and lower cross syndromes which suggests that the body is somehow “out of alignment,” that part of the body is weak and part of the body is tight and therefore stretching exercises need to be prescribed. This all comes under the umbrella of postural issues, again a much larger topic, but again the old tropes of posture being the cause of many peoples’ issues is finally starting to be debunked by science and evidence.
One example of this is the idea that the ITB can be stretched, which is an all too common myth that is widely troped in the health and fitness world. ITB stretches are commonly prescribed by healthcare professionals or the internet which is full of articles proclaiming that the one solution to ITB syndrome or runner’s knee is to stretch or roll it. Firstly, biomechanically it is extremely difficult to place the ITB in a position that generates a suitable stretch force. Secondly and more importantly the ITB is not a muscle instead it is a thick piece of connective tissue firmly anchored into the femur and is nearly impossible to deform. Mechanical testing has shown that at best a couple of millimetres can be achieved but then it will simply return to its normal resting position, making it pointless to stretch it in the first place.
In this area I will admit to my biases, in which I believe the majority of issues are usually as a result of load management, either they are over-loaded or under-loaded and a suitable dosage of resistance exercises to strengthen will help a patients’ problem. I do not believe that in the majority of cases flexibility is the cause of the problem. My preference to resistance training is also due to the many additional benefits resistance training conveys whereas stretching can only help to improve flexibility and little else.
Stretching For Flexibility
Finally, we get to the positive stuff. Yes, stretching just like ronseil does exactly as it says on the tin. By this it means that if you stretch over a period of time, although the results vary across the human population, there will be a measurable improvement, hurrah. There is also plenty of evidence, double hurrah.
But and this is a big BUT… Just because it does improve flexibility and therefore ROM, is flexibility actually a massive problem for people. There is no correlation between a lack of flexibility and an increase in injury, we know that stretching does little for perceived muscle “stiffness.” The vast majority of people are able to perform the activities they need to get through life and even sport without their perceived lack of flexibility actually getting in the way. For example, a commonly used example of someone’s perceived lack of flexibility is whether someone can touch their toes without bending your knees. If you can do great if you can’t who cares, it is measuring nothing other than whether you can touch your toes and the last time I checked that wasn’t necessarily an important factor in helping you get through life and more importantly is it not a measure of someone’s health. Furthermore, that’s why we have knees that bend so that we can reach our toes.
Flexibility as mentioned before is not a good measure of health, you can be fit for a particular activity but that does not make you healthy. Even so, for a very small minority of people in a very narrow field e.g. gymnastics flexibility is important.
We are in agreement that stretching can improve flexibility, but that is possibly where the agreement ends as there are a couple of further issues. Firstly, what is the correct dosage of stretching required to get these improvements. Unfortunately, even the stretch gurus can’t agree with each other for the simple reason, we do not know. Some studies have advocated holding a stretch for up to 20 mins to get the best effects. Who in the world has time for that? Do we need to do it every day or every other day? Is it best to hold the stretch for 5 secs or 5mins? As I said before we just don’t know.
The second issue and again this is probably the most important and most contentious. That is, what is actually happening when a muscle gets stretched? The long held belief is that when you stretch the muscle over a long period of time you are actually lengthening the muscle. I.e. there is actual permanent, plastic and lasting deformation of the muscle. Numerous studies have tried to prove this theory but have failed to do so. Weppler et al in their study concluded that; “growing research refutes these mechanical theories, suggesting instead that in subjects who are asymptomatic, increases in muscle extensibility observed immediately after a single stretching session and after short- term (3- to 8-week) stretching regimens are predominantly due to modification in subjects sensation.” This is a potentially extremely controversial view point, which I will try to explain below.
After many hundreds of years studying the human body and the thousands and thousands articles trying to prove or disprove certain theories there is still lots that we don’t know about the human body. The beauty of research though is that we are continually evolving and understanding the body better and better. It wasn’t too long ago that we thought the mind and the brain was separate to the rest of the body. The above theory suggests that it is about the body’s tolerance to a stretch that is important. In other words the muscle doesn’t elongate but our willingness to elongate does. The body has an ingrained stop system or safety mechanism to prevent us pushing our bodies to the extreme and injuring ourselves. What stretching appears to do is to tell the brain and nervous system that its ok to push the muscle just a little but further, the body is an amazing thing.
One example of this idea of tricking the nervous system for better flexibility is that by adding vibration even highly flexible athletes can get get further gains. This debate, as with most things that concern the human body will rage for many years but this is healthy and as long as we move with the current evidence we will continue to learn more about the human body but also to help us better understand the things we should be doing to be as healthy as possible.
Does Stretching Have Any Other Benefits
Ok so we can say stretching can increase ROM and flexibility even if we don’t exactly know why but does it convey any other benefits. Or does being flexible make you a healthier person? The answer to that question is most likely no. More flexible people do not live for longer, have a lower heart rate or blood pressure and they certainly do not have fewer injuries or pain. In fact, some argue that flexibility should be removed from the pillars of fitness as being flexible does not transfer across to other aspects of fitness.
I will refer to my previous bias of resistance/strength training. Not only is this component an essential ingredient in my line of work as a physiotherapist in helping people recover from injury, but the additional benefits that resistance training conveys to health outcome measures such as heart rate, blood pressure, mortality rate is also massively helpful and important. From a personal point of view if I only had a limited amount of time I would want to concentrate my time which provided me multiple benefits rather than just one.
Should I Stretch Then?
I expect you may think I am going to say no but I am not. Stretching for some people is enjoyable and if you enjoy it brilliant keep doing it. If you don’t stretch but are always feeling guilty that you should stretch more then now you don’t have to feel so guilty. There are times that I occasionally stretch but its done with the knowledge that its just a brief feel good factor and then its gone. What this blog has hopefully done is to get you asking questions about your stretching routine and whether it is as important as you have been led to believe. If you are stretching a lot but not doing much resistance training you may want to consider changing your plan to reduce the amount of stretching and make some room for strengthening.
Key Take Home Points
- Stretching should not be incorporated into any routine in the belief that it will help improve athletic performance.
- Stretching does not help to prevent injuries and in some cases may increase the chance of injury, it will also not reduce post exercise DOMS
- Stretching does increase flexibility, one of the pillars of fitness, but does not convey any cross over effects to the other tenets of fitness or provide many additional health benefits, this questions its utility to continue being considered one of the tenets of fitness.
- Stretching has a limited use in the rehabilitation world and other tools should be more utilised such as resistance training.
- Having said that if you like stretching then feel free to carry on, undeniably it can feel good for a little while but hopefully now you are more aware that you are likely just scratching an itch rather than benefitting your body in the long term.