Abstract
[Purpose] To investigate the relationships between pre-landing ankle muscle activities and ankle position at ground contact during single-leg drop landing. [Subjects] Nine healthy subjects (4 men and 5 women, a total of 18 legs) participated in this study. [Methods] The ankle dorsiflexion and inversion angles, EMG activities of the peroneus longus (PL), tibialis anterior (TA), and gastrocnemius medialis (GM) were recorded during a single-leg drop landing from a 30-cm high box. The integrated EMG (IEMG) activity during the pre-landing (100 ms before ground contact), muscle activity ratio for the ankle plantarflexor and dorsiflexor, and the invertor and evertor muscles were calculated using each IEMG activity. [Results] There was a significant positive correlation between TA pre-landing IEMG activity and ankle inversion angle at ground contact, as well as GM pre-landing IEMG activity and ankle dorsiflexion angle at ground contact. Moreover, TA IEMG activity relative to PL and GM IEMG activities were significantly associated with ankle inversion angle at ground contact. [Conclusion] These results suggest that the pre-landing ankle muscle activities and their ratios are associated with ankle position at ground contact.
