Which muscle decelerates pronation of the subtalar joint during the contact phase?

• A. Posterior tibialis tendon
• B. Peroneus longus tendon
• C. Tibialis anterior tendon
• D. Flexor digitorum longus tendon

Answer: (A)

The main action is eccentric control of hindfoot motion to limit pronation as the foot first contacts the ground. The posterior tibialis tendon acts as the primary dynamic stabilizer of the medial arch and subtalar joint, inverting the foot and supporting the arch. During the contact phase, it contracts eccentrically to decelerate the pronation driven by ground reaction forces, helping to keep the arch and hindfoot from overpronating and preparing a stable lever for propulsion.

The other tendons have different primary roles: the peroneus longus tends to evert the foot and support the lateral side and arches, not decelerate pronation; the tibialis anterior mainly dorsiflexes and inverts to control foot placement rather than limit subtalar pronation during stance; the flexor digitorum longus flexes the toes and assists plantarflexion, with only a secondary, indirect role in controlling subtalar pronation.