In early 2012, Li Na withdrew from the GDF Suez Open in Paris, France, due to a back injury, which had a great impact on her athletic status this year. It is reported that earlier in the Federation Cup, Li Na has suffered from a back injury and has been relying on acupuncture and physiotherapy to relieve the pain and fight with the injury. Tennis players because of the need for extremely strong low back strength, so athletes in the game and training, often occur back muscle injuries. How to prevent muscle strains? To avoid muscle strains during exercise, you can do some preparation before exercise: First, warm-up exercises must be as active as possible. Professional athletes are very important to the warm-up exercise, on the contrary, many of us ordinary people tend to pay less attention to the warm-up exercise, many people suddenly want to play on a whim immediately past the ball, which is not correct. Generally speaking, warm-up exercises should be about 10 – 20 minutes, through the relaxation of muscles, pulling movement, light activity “to remind” the muscle immediately to carry out a large amount of activity. Second, the amount of exercise should be gradual. The amount of exercise mainly includes exercise time and exercise load, many people usually half an hour of exercise, do not suddenly all of a sudden on the exercise 1 hour 2 hours; or the usual weight 15kg, suddenly increased to 30kg 40gk, a sudden increase in the amount of exercise is very easy to cause sports injuries. Third, strengthen the study of sports theory. High-level professional athletes are not just “limber”, the learning of sports theory is also crucial, many skill sports, if the sports posture is not correct, or sports skills are not standardized, are easy to cause sports injuries, amateurs should strengthen the learning of sports theory, master the correct method of exercise . Fourth, strengthen local protection. For example, wear protective gear, to strengthen the local tissue warmth and protection. Fifth, appropriate supplemental energy and electrolytes before exercise. For example, eat something, drink some sports drinks.