Injury to the anterior cruciate ligament (ACL) may have consequences for an athlete in the form of pain, decreased activity levels and early-onset osteoarthritis. Female athletes are at increased risk of injury, perhaps because of differences in neuromuscular function. Methods of identifying risk factors and effective prevention strategies for ACL injury have traditionally involved athletes of high school age or older. However by that age, the opportune time to intervene may have passed. This thesis involves a sequence of studies which measures the neuromuscular function of younger athletes, aged 10-14 years. First, the reliability of measuring strength and power of the lower extremity on an isokinetic dynamometer was explored. Torque and power of the hip flexors and knee extensors were the only measures with acceptable reliability. Conversely, peak velocity of all the tested hip and knee movements demonstrated acceptable reliability. A high amount of variability was found with all test movements, and so alternate tests should be used if measuring an individual athlete’s ability. From the data collected within the reliability study, a sex comparison was undertaken to determine if neuromuscular power differed at this young age. It was determined that girls and boys between 10 and 14 years of age do not differ in terms of knee or hip movement velocity or power. There is evidence to suggest that sex differences exist by adulthood; further research is required to determine when the disparity becomes apparent. The final project was to determine whether strength training would improve the manner in which young female athletes land from a jump; a common ACL injury mechanism. This randomized controlled trial found no difference between the intervention group who trained their legs, and the control group who trained their arms. However those athletes with the poorest landings appeared to improve their movement pattern regardless of training regime. This thesis contributes to the literature by providing evidence for measurement protocols for young athletes, introducing neuromuscular power instead of strength into the investigation of contributing factors to injury, and by furthering the examination of strength training as an effective component of prevention programs.