The so-called "core" is the middle link of the human body, that is, the area below the shoulder joint and above the hip joint, including the pelvis. It is a whole composed of waist, pelvis and hip joint, and contains 29 muscles.

Core muscle group is responsible for stabilizing the center of gravity and transmitting strength, which is the main link of the overall force, and plays an important role in the activity and force of upper and lower limbs.

Strong core muscle groups play a stabilizing and supporting role in body posture, sports skills and special technical movements in sports.