1, head rotation: stand or sit down, gently turn your head, 10 times or so. This can relax the neck muscles and increase the flexibility of the neck.

2. Shoulder Relaxation: When standing or sitting down, your arms naturally droop and gently swing in four directions with your shoulders as the axis, each direction 10 times. This can relax shoulder muscles and increase shoulder flexibility.

3, wrist flexion and extension: standing or sitting, arms naturally droop, and then slowly bend and extend the wrist, each action 10 times. This can relax the wrist and increase the flexibility of the wrist.

4. Waist rotation: stand or sit down, put your hands on your waist, and then gently rotate your waist in two directions, each direction 10 times. This can relax the waist muscles and increase the flexibility of the waist.

5, knee flexion and extension: standing or sitting, feet shoulder width, and then slowly flexion and extension of the knee joint, each action 10 times. This can relax the knee joint and increase its flexibility.

6, hip rotation: stand or sit down, put your hands on your hips, and then gently rotate your hips in the left and right directions, each direction 10 times. This can relax hip muscles and increase hip flexibility.

7. Ankle flexion and extension: Stand or sit with your feet shoulder-width, and then slowly bend and extend your ankle, each action 10 times. This can relax the ankle joint and increase its flexibility.

8. Deep breathing stretching: stand or sit, take a deep breath 10 times, and cooperate with stretching actions, such as stretching and tuck. This can relax the muscles of the whole body and increase the flexibility of the body.

Precautions for physical education class's preparatory activities:

1, warm-up exercise duration: The warm-up exercise duration should be adjusted according to individual circumstances and sports events. Generally speaking, the time of warm-up exercise should be about 5- 10 minutes to ensure that the body is fully warmed up and ready for the next exercise.

2. Action selection: When choosing warm-up exercises, you should choose simple actions that can cover all parts of the body, such as head rotation, shoulder relaxation, wrist flexion and extension, waist rotation, knee flexion and extension, hip rotation, ankle flexion and extension, etc. These exercises can help to relax muscles and joints in all parts and improve the flexibility and stability of the body.

3, the intensity of the action: in the process of warm-up, we should pay attention to control the intensity of the action. Too strong action may lead to accidental injuries such as muscle strain, while too weak action cannot achieve the effect of full preheating. Therefore, in the process of each exercise, we should pay moderate attention and amplitude to ensure that the body is fully warmed up.

4. Breathing: Pay attention to breathing when doing warm-up exercises. Deep breathing helps to relax the body and enhance endurance and flexibility. Therefore, in the process of each movement, we should pay attention to the rhythm and intensity of breathing, so that breathing and movement can be coordinated with each other.