The aim of this study was to identify changes in muscle activation by comparing muscle activities of the affected side (AS) and non-affected side (NAS) during eccentric and concentric exercises in runners with unilateral Achilles tendinopathy. The study was comprised of 18 participants consisting of men and women with chronic Achilles tendinopathy in a single leg who had more than 1 year of running experience. All subjects performed concentric and eccentric exercise with the Achilles tendon moving from full plantar flexion to full dorsiflexion for 8 seconds, and electromyography data was obtained. All muscles examined showed a significant increase in %maximal voluntary contraction (MVC) with concentric exercise compared with eccentric exercise. In comparison to the NAS, the AS showed significant increases in %MVC of the rectus femoris, tibialis anterior, and lateral gastrocnemius. All interaction effects of exercise methods and injuries exhibited statistically significant changes.
Runners with Achilles tendinopathy exhibit increases in medial gastrocnemius activity while performing eccentric exercise. e