Flexibility is one of the three qualities of the human body, along with strength and endurance. Some of the habitual terms and practices of its training are not quite scientific, and therefore need to be revised.  Flexibility training should be accurately guided, and it should not be limited to before and after exercise. It should be carried out throughout the day.  Even if you do not work out, you should do some related exercises to strengthen the range of motion of each major joint of body.