(1) Not enough warm-up time and insufficient body stretching. Stretch your legs every 15-20 minutes in class;

(2) Tighten the abdomen and jaw, make a fist in front of the face (defensive posture), keep breathing normally and don't hold your breath;

(3) Avoid training for a long time like professional athletes, and practice alternately with high and low exercise;

(4) Don't twist forward when kicking sideways, which will lead to the concentration of knee pressure, and stretching your toes will sprain your knee. You should twist your legs to your toes to reduce the lateral pressure on your knees.

(5) Don't stiffen your knees to reduce cushioning. Lift your knees when you turn around, otherwise you will sprain the cruciate ligament;

(6) When punching, the shoulder should drive the punching, and always look at the target before punching and kicking;

(7) Avoid kicking in crowded rooms;

(8) Avoid excessive elbow and knee exertion; Avoid dislocation due to excessive action when dodging or slapping, and avoid excessive twisting action;

(9) If the following situations occur, you can stop practicing (leg fatigue, local pain and discomfort, dizziness, increased heart rate, etc.). );