One of the main reasons exercise is heavily pushed for athletes and for the weekend gym goer, is the injury prevention effect of training. On top of the physiological effects, the psychological effects and even the social component- injury prevention is generally mentioned.
Van Beijsterveldt, et al; 2013 performed a literature review on this very question. They included all RCTs in English, German and Dutch from 4 of the largest medical databases in the world. Their inclusion criteria included that injury rates were the primary outcome of the study, that exercise was the primary intervention to reduce injury rates (and not for specific injuries eg ankle sprains), that they applied the program to soccer players ‘.
Six studies involving over 6000 players met all inclusions criteria. The results were contradictory. 2 studies indicated a statistically significant reduction in injury rates while 3 others showed overall prevention but no reduction in rates. 1 study showed no effect.
Given that no standardized training regimen exists for football, this is an excellent first step. If nothing else, it appears that exercise does prevent overall injury rates. At this time, using standardized testing and training may be the way to go.