Stretching before fitness is to warm up, which can help joint activities and make muscles quickly enter the state of exercise. Stretching after fitness is to relax, relieve tense muscles and accelerate muscle recovery.
This very beneficial stretching exercise is easily overlooked. Even if it is not ignored, many people have a poor understanding of stretching. You should know that different stretching actions can stretch to different muscle parts.
Traditional ideas suggest stretching after resistance training, not stretching before training.
Excessive stretching before training will improve joint flexibility, but it will also lead to a decline in joint stability. The sudden increase in the range of motion will also affect the control of the central nervous system on muscles, which will more easily lead to muscle strain in resistance training.
The main purpose of stretching after training is not to really lengthen the muscles, but because the muscles have more blood just after training.
At this time, stretching is helpful to improve the circulation of blood and tissue fluid, which is more conducive to recovery after training. Many fitness people mistakenly think that stretching after training is because resistance training itself will lead to shorter muscles, so they should lengthen muscles after training, but in fact, training itself is a kind of weight-bearing muscle stretching. There are centripetal contraction and centrifugal contraction (stretching) during training, so it will not lead to muscle shortening and tension. Unless overtraining or straining, this is why many bodybuilders rarely stretch, but there are no obvious physical restrictions. Compared with sedentary activities, it will lead to muscle tension and adhesion, and these people need to stretch and relax more.
Finally, stretching is usually used before and after exercise, but from a medical point of view, there is no evidence that stretching can prevent muscle soreness after exercise and cannot reduce sports injuries. But for runners, the previous stretching may be beneficial, and some athletes can increase their range of activities by stretching.
The above is my opinion, I hope it will help you.