Introduction: Appropriate muscle recruitment has a significant role in the stabilization of joints. The aim of this study is to investigate the effects of six weeks Plyometric training on performance and the feed-forward activation of calf muscles in active females with functional ankle instability in single leg drop landing.

Materials & methods: Thirty active females with functional ankle instability participated in this quasi-experimental study. The experimental group underwent six weeks of Pi-Yin Hung Plyometric training protocol during the period of 18 sessions. In order to assess the performance, functional tests (lateral hop and multiple hop tests) and ankle joint function assessment tool were used. Electrical activation assessments of peroneus longus, tibialis anterior and gastrocnemius muscles (in single leg drop landing task) were completed in the pre-test and post-test (after six weeks). SPSS Software version 20 was used in order to analyze the data (p<0.05).

Finding: Results revealed that after the implementation of six weeks Plyometric training, multiple hops testing time dropped significantly and lateral hop testing distance had a significant increase.

A significant increase in the feed-forward activation of peroneus longus and medial gastrocnemius was seen (p≤0.05), but there were no significant changes at the feed-forward activation of tibialis anterior (p<0.05).

Discussion & conclusions: Plyometric training by changing the feed-forward activation of peroneus longus and medial gastrocnemius muscles, improved lower extremity performance in patients with functional ankle instability and should be incorporated into rehabilitation programs for those with functional ankle instability.