 In response to high injury rates in soccer, the Fédération Internationale de Football Association FIFA developed an injury prevention program called the 11. It is designed to replace a standard warm-up and takes about 20 minutes to complete. The program has proven remarkably effective in decreasing the rate of injury in soccer players. However, uptake of the 11 has been less than desired. Adoption of the program may be increased if additional benefits can be demonstrated and the program is introduced at a younger age. The goals of this study are to 1establish that young athletes can tolerate the program, and 2measure the effects of the 11 program on the physical performance of 10-12 year old girls. Three teams will be randomly assigned to the intervention group and carry out the 11 program for the duration of the indoor soccer season. Another 3 teams will continue with their usual warm-up. Pre- and post-intervention, balance, agility, core strength and movement control will be assessed in all athletes. The investigators hypothesize that the athletes will tolerate the program well and that the intervention group will improve on the performance tests significantly more than the control group. 