1, safety principle. It is very important to warm up before exercise and stretch after exercise. Stretching after exercise helps to relax muscles and improve muscle elasticity, which is one of the "magic weapons" to reduce sports injuries. The stretching exercise time should be at least 10 minute, or about 1/3 of the exercise duration.

2. The principle of comprehensiveness. Different types of sports bring different fitness effects. Sports categories should be a little miscellaneous, preferably including aerobic exercise, strength training and flexibility training.

3. The principle of accuracy. As long as the action standard and exercise load are reasonable, sports injuries can be avoided. The main causes of sports injury accidents are "fake" posture, no effort and irregular movements.

4. The principle of gradualism. The frequency of exercise varies from person to person, but you should exercise at least three times a week, and it is best to gradually increase it to five times a week to ensure the fitness effect. No matter what the level of physical fitness is, you should do what you can when exercising, and you can't ignore the signals sent by your body. If you have dizziness, dizziness, chest pain, nausea, shortness of breath, palpitation, vomiting and other symptoms during exercise, you should stop exercising immediately and seek medical advice in time.

5. The principle of perseverance. To achieve good fitness effect, to overcome their inertia, it is essential to insist on exercise.