Females incur non-contact anterior cruciate ligament injuries at a rate four-six times higher than their male peers. This increased incidence may be attributed to lower extremity biomechanical differences between girls and boys during landings from athletic maneuvers. While most of the published literature focuses on a postpubsent population, there is little data investigating the differences between prepubescent girls and boys. The purpose of this study was to investigate if biomechanical differences at the knee were present between prepubescent girls and boys during a landing and jumping task.

Nineteen (10 boys / 9 girls) prepubescent soccer players participated in this study. A motion analysis system and force plate was used to collect data. Knee flexion/extension angle, varus/valgus angle, vertical ground reaction forces and anterior tibial shear force were assessed during a vertical jump and landing task.

Statistical analysis revealed that there were no significant differences between genders for vertical ground reaction force, peak posterior ground reaction force, anterior tibial shear force, knee flexion/extension and varus/valgus angle at peak vertical ground reaction force and varus/valgus angle at initial contact with the force plate. There was significance between genders for the knee flexion/extension angle at initial contact with the force plate. The results of this research would indicate that the biomechanical differences of the lower extremity may emerge during or after puberty. Based upon these findings, it may be appropriate to initiate injury prevention programs at an earlier age to aid in correcting the high risk biomechanical differences typically seen in the postpubescent population.