Abstract
[Purpose] The purpose of this study was to determine whether gender differences exist in the activity and ratio of the vastus medialis oblique and vastus lateralis muscles when performing a vertical drop landing. [Subjects] Thirty participants (15 males, 15 females) dropped from the height of their lower leg. [Methods] The EMG activities of the vastus medialis oblique and vastus lateralis muscles were recorded during vertical drop landing using surface electrodes. [Results] The muscle activities and the ratio of both muscles were significantly higher for males than for females. The muscle activity of the vastus medialis oblique muscle was 36.3% for males and 20.2% for females, and that of the lateralis muscle was 34.2% for males and 26.1% for females. The mean ratio of the vastus medialis oblique muscle : vastus lateralis muscle was 1.07 for males and 0.78 for females. [Conclusion] For females, drop landing in females may increase the likelihood of patellofemoral pain syndrome.
