Stretching is a controversial topic in sports. At present, most scientific research results strongly show that static stretching before exercise will not prevent excessive injury, but may affect athletes' performance. Rostak, a South African physiologist and co-author of the online edition of Sports Science, said: Stretching has a great influence on the nervous system, and reflected waves can prevent muscles from overstretching. This reflected wave is activated by static stretching, which will cause muscle contraction to protect itself. It was previously found that high jumpers would jump lower if they stretched statically before taking off, because they could not generate enough energy. At the same time, other studies, such as the report of New IAAF, also found that static stretching seems to have little effect on preventing sports injuries, especially the common excessive injuries in running. Malac mchugh, director of sports medicine and sports injury research at Nicholas college, said: the current research results are consistent with the known conclusions. In April, he also published a paper on comprehensive examination of 10 annual tensile value in Scandinavian Journal of Sports Medicine and Science, and he was the main author of the paper. But many people still decide to continue their routine stretching before running. "It is really difficult to divide athletes who have been stretching into non-stretching groups," said Alan Ross, a former member of the American Athletics Committee and coordinator of the study. As soon as they realized that they couldn't stretch before running for three months, they didn't want to take part in the study. It took researchers more than two years to persuade enough people to join in, complete the research activities, and obtain enough data to prove this important result.