Programmer Health Path: Do you need to stretch before and after fitness?

Many people do stretching while exercising or playing sports, others do not stretch, but feel they should do it, and some people simply do not see any reason to stretch. Most people think stretching makes them more flexible. Some people think stretching reduces the risk of injury, reduces pain after exercise, or improves athletic performance. Optimists think all of these are.
　　
But do we really need to stretch during exercise? Can La Shijin increase flexibility, reduce risk of injury, reduce pain and improve athletic performance? The answer is both and no.
　　
Is stretching really necessary before and after exercise?
　　
Some people believe stretching can reduce the risk of injury, reduce pain after exercise, or enhance athletic performance. Natalie/flickr, CC BY-NC
　　
The only way for researchers to get a real clear understanding of the effects of stretching is to do random tests.
　　
In randomised trials, the use of lots to allocate each participant was treated (in this case, stretching) or not accepted. The results of the test (injury, muscle soreness or athletic performance) of the subjects who had been stretched were then compared to what had not been done. The difference between the two sets of results tells us the effect of stretching.
　　
The first two trials of tensile effects on the risk of injury were performed on 2,631 army recruits, and the results showed that conventional stretching before the three-month exercise did not significantly reduce the risk of injury. A recent experiment with 2,377 recreational players has resulted in very similar results: three months of regular stretching have little or no impact on the risk of injury.
　　
Together, these tests strongly suggest that stretching does not significantly reduce the risk of injury.
　　
Some other randomized trials studied the effects of stretching before and after physical activity on post-workout soreness. They say stretching does reduce pain, but in a small way.
　　
The evaluation of these trials concludes that:
　　
Muscle stretching, whether before, after, or before and after exercise, does not produce clinically significant reductions in healthy adults for delayed muscle soreness.
　　
Flexibility and strength
　　
The effect of stretching on athletic performance is less clear, or at least more complex.
　　
Few randomised trials measured athletic results as a result. On the contrary, most trials examined the effects of stretching on the two intermediate levels that may affect athletic performance: flexibility and muscle-producing power.
　　
To understand the effects of stretching on flexibility and muscle strength, it is necessary to differentiate between its acute and chronic effects. The acute effect appears immediately after stretching, while the chronic effect may occur after several months or years of repeated stretching.
　　
Stretching is an acute increase in flexibility: after just a few seconds or a few minutes of stretching, the joints move more and hinder less movement. But this effect is temporary. Once the stretch stops, the flexibility returns to the level before stretching, and the response is basically completed within minutes of the end of the stretch.
　　
It is possible, but not quite certain, that stretching has a chronic effect on flexibility. Regular stretching can stimulate the adaptability of muscles and other tissues, resulting in lasting flexibility.
　　
Daily observation shows that this is true because the ballet dancer and the yoga instructor stretch a lot and are often more flexible than the rest of us. However, while it seems obvious that regular stretching makes people more flexible, it has proved very difficult to demonstrate in controlled experiments.
　　
Stretching does allow people to withstand more stretching. In other words, it makes people feel that they can stretch more. And this increased stretch latitude can make people feel more flexible, even if they are not flexible.
　　
Either way, the effect of stretching on flexibility-acute or chronic-can be used to improve the performance of certain movements. Hurdles or gymnasts, for example, may perform better if they are more flexible. More generally, it may increase the performance of sports that require flexibility.
　　
Another form of stretching that may affect the way you score is through its effect on muscle power. The clearest conclusion from human studies is that stretching usually has a slight, temporary reduction in muscle strength.
　　
This suggests that it is unwise to stretch the muscles before exercising a lot of muscle power.
　　
It seems that if the hurdles are better flexible, they can perform better. Melinda Huntley/flickr, CC by-nc-nd
　　
Stretch or not?
　　
For recreational sports people, these findings suggest that stretching has a small benefit and may not be harmful. If you like stretching, do it, and if you don't like stretching, don't do it, and don't feel guilty.
　　
For high-level athletes, relationships are more important and decisions are more difficult. Stretching can increase athletic performance that requires a lot of flexibility, but may temporarily reduce muscle strength; If you're a hurdle rather than a weight lifter, stretching makes more sense.
　　
These conclusions have some caveats. First, most of the study of tensile effects investigates the effect of "static" stretching--applying and continuously stretching for a short period of time. There are many other forms of stretching, but most have only relatively few studies, or only poor quality studies.
　　
It is also important to note that although there are many understandings of the acute effects of stretching, there is little knowledge about its chronic effects. No one has tried a few years of regular tensile randomised trials.
　　
Often stretching can have a significant effect in the long term. But then again, its long-term impact may be harmful, or there is no long-term impact at all. We just don't know.
　　
Similarly, a good evidence that one stretching method is superior to another, or a long-term effect of a particular type of stretching, does not exist.
　　
Use a more positive note as a conclusion: although it appears that stretching does not significantly reduce the risk of injury, there is good evidence that the warm-up will be. A strong, well-structured, positive warm-up can greatly reduce the risk of injury, so try to do it the next time you exercise.

Programmer Health Path: Do you need to stretch before and after fitness?