Stretching... is it worth it?
Often when stretching is mentioned or spoken about, it is positioned within the warm-up and/or cool down component, or within a rehabilitation setting. Regardless where the stretching modality is placed, normally the wanted outcome is to increase flexibility (flexibility defined loosely as the range of motion at the particular joint) within a joint or a group of joints.
This sounds reasonable and perhaps even thought of as best practice for different populations, such as recreational athletes, young athletes and even elite athletes. However, we have to appreciate and understand that just like strength training, aerobic training and power training, flexibility (and with that a stretching protocol) specific adaptations to muscles, musculotendon units, ligaments and joint capsules will occur. Therefore, we have to consider this with some thought, rather than just recklessly stretching different joints and parts of the body, with the notion that, more or a greater range of motion is always better no matter the sport or the environment.
With that said, if we consider that the below factors change or alter flexibility, this will start to paint a picture around the use of stretching as a training modality.
We know that age plays a major factor in one’s flexibility or range of motion, with the idea that younger people have a greater range of motion, and older people see a decline. The reason for this will be mentioned in the mechanical considerations. We also know that females have a greater range of motion than males, plus other factors such as activity level and sport played. Simply put, the more active you are, you generally have a greater range of motion than someone who is sedentary.
The really important and interesting areas to consider, especially for strength and conditioning coaches at the Lab, are that younger people (especially younger female athletes) tend to have a large range of motion (and, yes, this is a generalization). This brings me onto the mechanical considerations of the tissues within the body. It is well understood that muscles and tendons generate and transmit forces throughout the body. In motion or locomotor actions, like running, sprinting and jumping the muscles and tendons act like springs, absorbing and releasing energy, to decrease or save metabolic activity, driving overall economy.
When we compare the muscles and tendons to springs, we then take this a little further by looking at the structure of the spring, and rate its function, using the terms stiffness or compliance. A spring which has more stiffness will deform less, than a spring which is more compliant, when a given force is applied to the structure. Furthermore, the spring which has greater stiffness will transmit the forces quicker than the compliant spring, however, the compliant spring can absorb and release more energy, therefore, increasing its overall elastic-strain energy efficiency (please be aware that some heat will be lost within the compliant spring).
Trying to understand these mechanical principles are important when we transfer this to training, especially in young athletes. As stated previously, young people tend to have a large range of motion, and this is generally without any specific training. This is probably due to the fact that young people’s muscles and especially tendons are extremely compliant. Therefore, if we start to prescribe more stretching, as we believe that it may help within the warm-up or cool down as a part of an injury prevention program, we have to tread very carefully, as more stretching will increase muscle and tendon compliance. On the other hand, a host of evidence has suggested that different strength training will increase the stiffness, again especially in the tendon or musculotendon unit, and has shown to improve running economy (running economy is the relationship between the amount of oxygen used to a given running speed. Thus, if you can run faster using less oxygen it is suggested that you have a greater running economy).
So, what does this mean practically?
Generally stretching, just like any other training modality is just a ‘training tool’ to use when needed. Given the evidence around young people and young athletes, it may be best practice to concentrate on developing their skill in strength training, plyometric training and the sport they play, as other general attributes will also follow.
If you feel that stretching, in the warm-up and/or cool down, plays a part in reducing injuries, this notion is extremely difficult to answer, as injuries are normally multifactorial in their nature, and suggesting that stretching will reduce or aid this somehow, is definitely a giant leap. Additionally, if we consider the amount or volume of stretching required to make a significant difference in the muscle and/or tendon practically this may be unrealistic. For example, studies have reported that stretching twice a day, seven days a week for eight weeks increased tendon compliance. I very much doubt that people are following this type of stretching protocol!
At the Lab, as we coach young athletes, and prepare them for a life of sport and activity, we tend to use a RAMP (raise temperature, activation, dynamic mobility, potentiate) approach for training warm-ups, as the evidence is quite strong on training outcomes. Regarding recovery after training, lifestyle factors such as optimal sleep, nutrition, hydration and general rest, are all key factors.
Closing thought. If an older person (mid 40’s) asked me about stretching or attending a stretch-type class, I would promote it for them, especially if they fell into the low activity group. I would even pay for their first class, as the benefits are difficult to argue. If I see young athlete’s, let’s say, under 10 girls football team, static stretching before the game as a part of their warm-up, does that bother me? Not really, as the amount of stretching will not make much difference!! I just hope that they all visit the Lab one day, where they can participant in more skill training, have fun, develop overall resilience and confidence, leading them to reaching their individual potential.