However, we often are unaware that despite a great number of scientific studies, there is still no evidence that stretching is useful from a running training point of view. Moreover, being aware of the biomechanics of movement and knowing the anatomical basis of muscle structure and function, one might be tempted to conclude that stretching often conflicts with the goals we want to achieve through running training.
Did famous runners achieve great results because they were well stretched? Of course not. Let me quote a short story about Eliud Kipchoge, whose running achievements need no introduction:
He was extremely inflexible. After an easy morning run (16km in 1hr10mins), I stretched with the group. Most of them were fairly flexible in the hamstrings (ie. standing straight legged and bending over to touch your toes with your knees straight and being able to touch your toes. Eliud was miles off). He was nowhere near touching his toes! They all found it hilarious that he couldn’t come close to touching his toes.
Matt Fox for SweatElite.co, “Training with Eliud Kipchoge – 5 Things That Surprised Me”
Types of stretching
Static
Static stretching is defined as inducing a state of tension in a selected group of muscles and maintaining this state for 15-30 seconds. It can be performed alone or by a partner.
The risk of injury as a result of stretching alone is low. This type of stretching is good for achieving stretching of selected groups of connective tissues (if needed). The stretch should be to the point of mild discomfort (we should not feel pain). Static stretching will be better on rest days and after intense workouts, also as part of a relaxation practice.
Our muscles have viscoelastic abilities, meaning they can stretch. This is natural to the nature of their functioning. The length of a muscle is usually genetically determined and does not change during our lifetime. Therefore, static stretching may cause not so much lengthening of the muscle or increasing its elasticity, but simply increasing its susceptibility to stretching (we are able to withstand more tension while stretching).
Dynamic
Dynamic stretching is the stretching of a selected group of muscles by performing movements with selected parts of the body throughout the joint range, causing momentary tension (e.g. leg and arm waving).
This type of stretching is more risky, as it requires a lot of feeling, and stretching the tissues too much can cause significant pain.
For this reason, dynamic stretching, if we already like doing it, will be a good choice for the warm-up time. Of course, if we have to warm up in this way at all, because during the preparation for the workout many different other exercises can be used that are simply more effective.
Research does not show the superiority of static stretching over dynamic stretching or vice versa when it comes to increasing range of motion alone. Their effects are similar. However, dynamic stretching has the advantage of not being linked to a reduction in muscle strength or a greater risk of injury, especially if performed before a workout.
PNF stretching
There are many other improved stretching methods that can give better results than the above. One of these is PNF stretching, or Prioprioreceptive Neuromuscular Facilitation. It involves adding isometric contraction of the muscle to static stretching for 5 to 10 seconds.
This type of movement induced on the muscle takes advantage of the fact that the tissue relaxes faster immediately after the contraction of the muscle, thanks to the Golgi tendon organs. This method exploits the insensitivity of tissues to static stretch and the fact that their activation is triggered by contraction of adjacent muscles. In other words, the earlier contraction of a muscle a moment later, immediately after relaxation, allows it to stretch more easily.
PNF stretching requires more effort, so it will not be good soon after an intense workout. It also causes some muscle fatigue, so static stretching will be a better option on rest and recovery days.
Stretching during running training
Stretching and running
In general, static stretching provides the most benefit in sports that require a lot of flexibility, such as gymnastics or dance. Dynamic stretching works better in sports where running or jumping is a major component.
One scientific study, which analysed around 2,500 individuals, found that stretching for better recovery reduced symptoms of muscle soreness by only 1-4 points on a 100-point scale. So it's too little to claim that stretching has a positive effect on this aspect of our recovery.
Stretching during rehabilitation
Stretching is also used as part of rehabilitation. It is indicated when we need to increase the length of a muscle or its range of motion, or to align the length of collagen fibres when healing a damaged muscle.
When recovering from an injury to the muscles of the sciatic-shin group, research indicates that static stretching is more effective. Patients doing more intensive stretching exercises recovered from their injury more quickly. This required 6 to 8 weeks of exercise, however, it should be emphasised that these effects are strongly influenced by the individual predisposition of the specific person.
It should also be noted that it is difficult to unequivocally determine the effectiveness of stretching in the case of injury treatment, because usually in such cases other exercises, including strengthening exercises, were also prescribed, so it is difficult to isolate the effects of stretching alone.
It is also possible that stretching will be useful if we need to increase the range of motion of a muscle. If we lead a sedentary lifestyle and our muscles are severely contracted we may experience symptoms of shortened muscles. It is worth consulting a physiotherapist as to whether there is a need to stretch in a particular area, if so it is worth doing it correctly to achieve a specific effect, and then doing stretching from time to time to maintain the level of flexibility achieved.
Stretching before training
It is commonly believed that stretching should be performed as a warm-up, as it is a great activity to prepare the musculoskeletal system for a specific workout. However, research shows that stretching is not a very effective form of warm-up. There are many exercises that work much better. As part of the warm-up, include elements of dynamic stretching, which can help you reach your target ranges of motion and also allows you to warm up slightly.
Given that we run largely through the elasticity of muscle and tendon systems, static stretching before training is not a recommended procedure. When training, we want well-functioning and properly toned muscles, not relaxed and flabby muscle bands (of course, this is an overstatement). There is reason to believe that static stretching before training reduces muscle strength, and can also increase (up to about 30%) the risk of injury. However, the reason for this is not fully known.
Even more so, there are no scientific studies that confirm the positive effects of stretching on training effects.
It has also not been proven that stretching prevents injuries. This is a myth spread on the basis of religion and belief. Many people say: "I stretch and see, it produces results, I have no injuries". But is that proof? It's the same as saying, "I stretch and I'm not hungry".
Stretching after training
Studies on mice and rabbits (let's hope they were just running and pacing themselves), showed that systematic stretching increased levels of Insulin-like Growth Factor (IGF-1) and Mechanical Growth Factor (MGF). IGF-1 serves as a mechanism not only to increase strength, but also enhances recovery. So if stretching causes IGF-1 and MGF levels to increase, there is potential for it to be very beneficial. The release of these hormones during post-workout stretching may help initiate faster cell and tissue repair, thereby augmenting and accelerating the adaptation process and ultimately improving performance.
Other studies have found that stretching combined with strength training produced greater strength gains than strength training alone without stretching. The theory related to IGF-1 and MGF may support these results.
Stretching can make us run slower
However, there is also a theory that runners whose tendons and ligaments are too loose, have too much 'slack' in their system, will not be able to reach their full potential and utilise the elastic energy that is created when running. Running is an activity that requires the use of a lot of energy stored in the elastic elements and returned. Stretching them too much will cause them not to function as they should.
Stretching techniques
- Given the properties of the tissue, the greatest deformation occurs after the first stretch. After four repetitions there is no longer much change in the tension of the tissue, so it is most worthwhile (if we already have to for some reason) to do a maximum of four series.
- It takes between 12 and 18 seconds to achieve tissue relaxation during a stretch after the initial tension, so there is no need to hold in a stretched state for more than 20 seconds. Some studies say a maximum of 30 seconds.
- If we bring the tissue to stretch, it will not seek to return to its previous length immediately, it will not shorten as quickly. However, the changes will not be permanent because of its elastic properties and it will eventually return to its previous state. Permanent changes can only occur through a process of adaptation and transformation of the connective tissues, not through mechanical deformation. Some research has shown that the best way to stretch tissue is to do stretching exercises every four hours (which could mean that it takes about that long to stretch the tissue before it returns to its previous length).
- We don't stretch cold muscles, we only do stretching after a 5-10 minute warm-up.
- Tendons are less stiff in the evening, if we want to stretch this is the best time. This is due to the increased body temperature in the evening. This is when PNF stretching (an improved form of static stretching) is best performed. If we want to stretch in the morning, dynamic exercises are best.
- PNF stretching: 2-3 seconds of tension, then relaxation and stretch for 10-15 seconds. Over time, build up to 10 seconds of tension and then stretch for up to 30 seconds. Repeat up to 4 times. It takes time, so you can stretch two or three muscle groups at one time, then move on to another group the following week.
Conclusions
Stretching should be practised when there is a real reason to do so. And in the correct way, according to human anatomy and physiology. We should trust our own body, that as a result of adaptation to exertion and exercises, with which we systematically load it, it can adapt to more economical, efficient and safe work.
Of course, stretching should not be treated completely as the ultimate evil. In many cases, mainly in cases of therapy during an injury, if performed according to the recommendations of a physiotherapist, it can support the process of healing of the muscular system and its return to the desired state.
However, do not expect miracles from stretching and do not treat it as a religious practice. It is worth knowing what you are doing and what its purpose is. And do it in a fully conscious way.
Sources
- Herbert RD, de Noronha M, Kamper SJ. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database of Systematic Reviews 2011, Issue 7.
http://www.ncbi.nlm.nih.gov/pubmed/17943822 - Nuzzo JL. The Case for Retiring Flexibility as a Major Component of Physical Fitness. Sports Med. 2020 May.
https://pubmed.ncbi.nlm.nih.gov/31845202/ - Phil Page, Current concepts in muscle stretching for exercise and rehabilitation.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3273886/#!po=10.4167