Dorsiflexion of the ankle is limited with tightness of the gastrocnemius muscle. The gastrocnemius muscle spans across the knee joint. The gastrocnemius muscle relaxes with flexion of the knee and this improves the ankle dorsiflexion. This knee flexion test measures the range of ankle dorsiflexion with the knee flexed and the knee straight. More ankle dorsiflexion with the knee flexed indicates gastrocnemius tightness. With Achilles tendon tightness or contracture, ankle dorsiflexion is the same with knee extension and flexion. With Achilles tendon tightness or contracture, ankle dorsiflexion is the same with knee extension and flexion. The degree of dorsiflexion does not change regardless of the knee position involving tightness of the Achilles tendon.
