1- Short-term fatigue, which is called "pole" in running terminology, usually occurs around 800 meters. It will be easier to stick to this "pole". Of course, this does not mean that you will relax like walking. Stick to it, but don't run too much. Be careful of knee joint injury.

2- Accumulated accumulation may be that you don't arrange rest scientifically, and if you keep running, it will accumulate more and more.

3- Continuous exercise of leg strength or physical fitness, no scientific arrangement for rest.

4- unscientific exercise mode, which comprehensively affects muscle recovery and needs to be improved. Please consult a professional.