Reduced Intratendinous Sliding in Achilles Tendinopathy During Active Plantarflexion Regardless of Horizontal Foot Position.

We provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome.