Where do you think football players injure themselves most often?
Experience shows that the ischiocrural muscles, i.e. the back of the thigh, are the front-runners. Strains in the hamstrings, i.e. the back of the thigh muscles, are one of the most common injury patterns in soccer - both professionals and amateurs are affected time and again.
The most important question is: What is the cause?
One reason could be muscular imbalances of the anterior and posterior muscle chain.