Ankle strength and gait asymmetries in patients with insertional achilles tendinopathy

Insertional Achilles tendinopathy (IAT) is a common condition in recreational athletes that causes heel pain. The recurring pain may trigger load compensation mechanisms and concomitantly lead to strength and gait asymmetries. 15 patients with unilateral IAT performed maximal isometric ankle plantar and dorsiflexion strength tests at two ankle positions (-10° and 20° plantar flexion). Kinematic and kinetic parameters were assessed using gait analysis. Interestingly, the involved limb showed lower plantar flexion strength (-15%) at the 20° position only, suggesting that patients with IAT experience functional limitations at more plantar flexed positions. This finding was supported by the lower unloading rate (-11%) of the involved limb during gait, which occurs in the final stance phase and thus also in a plantar flexed position. Patients with unilateral IAT should be aware that their condition may induce angle-dependent plantar flexor weakness and asymmetric unloading during the final stance phase.