Purpose of stretching
In media you will often find articles about stretching, including discussions about whether it helps or not for different purposes. What are the different opinions based on, and what kind of results exists from research?
Stretching is used with many purposes. One of them is to increase the range of motion for specific activities, while others do stretching with the puprpose of reducing soreness after training. However, whether stretching actually reduces soreness after training is still being debated.
Stretching is also being used by athletes and physioterapists as a part of treatment and recovery related to injuries, or prevention of injuries. The target is then to increase the range of movement around a joint, or to prevent reduced circulation in tissue after training sessions. For a physioterapist the target of increased range of movement is often connected to treatment of an injury that has resulted in shortening of a muscle.
Stretching may by itself increase blood circulation and by that contribute to relaxation in muscles, which is positive. Further, stretching before training sessions can prepare the body for physical activity.
Results from research
As an example, a research project conducted in Denmark has investigated the effect of several stretching methods for hamstrings (backside of the thigh), with respecty to range of movement. Conclusion: 3 weeks of stretching (5 x 45 seconds, 2 times per day) of the backside of the thighs significantly increased the range of movement.This result is typical. A number of studies has demonstrated that stretching has a significant effect on increasing flexibility and range of movement.
The direct effect on performance
Different research projects have been investigating if improved performance is achieved if stretching is performed directly before the activity. Some of the studies conclude that maximal performance is reduced significantly for jumping and sprint running that is performed just after static stretching. Other studies do not find any positive or negative effect of stretching. In other words, there is nothing that indicates any positive effect from stretching on performance of maximal power exercises. If however the performance requires large ranges of motion, research concludes that there is a significant positive effect of stretching. Be aware that there is a difference between dynamic and static stretching, and that dynamic stretching and flexibility training can have a positive effect on plyos and explosivity.
The effect of running after long term stretching and flexibility training
Some research has indicated that a high level of flexibility actually may have a negative effect on running effieciency, but in general the knowledge about the relation between stretching and performance is limited.
The effect of stretching on risk of injury
Even many believe that stretching exercises have preventive effect towards running injuries, no research exist that gives evidence of such effects.
The effect of stretching on muscle soreness after training
No studies have been conducted giving evidence that stretching reduces muscle soreness. However, many people have a feeling of well being when stretching after training. If so, just continue with it.
My advice for stretching
Stretching increases flexibility, but the mechanism behind increased flexibility and range of motion is uncertain. Different theories exist stating that muscles and tendons become longer and more flexible, but this has never been proven scientifically.
Reduced flexibility increases the risk of injuries My advice is therefore: With an injury or if you wish to increase the range of movement, you should stretch several times per day. The exercises shall then be specific, with a starting position where the relevant muscle is stretched in an optimal way, and keep 45 seconds.
You do not avoid soreness after training by stretching. Then it is better to finalise the running session by continuing with a significantly lower speed for some minutes the last part of the session. This will maintain the circulation in the tissue.
Author: Hege Erichsen