Which muscle group eccentrically controls plantarflexion during loading response to prevent foot slap?

Which muscle group eccentrically controls plantarflexion during loading response to prevent foot slap?

• A. Tibialis anterior
• B. Gastrocnemius
• C. Soleus
• D. Peroneus longus

Answer: (A)

During loading response, the ankle moves from heel strike into controlled plantarflexion as weight is borne. The key to preventing foot slap is the dorsiflexor group contracting eccentrically to slow this plantarflexion. The tibialis anterior lengthens under tension while it still contracts to pull the foot into dorsiflexion, acting as a brake on sudden plantarflexion. If this eccentric dorsiflexor control is lacking, the foot can drop and slap the ground. Gastrocnemius and soleus are plantarflexors themselves and contribute to control in other phases, but they’re not the primary eccentric brake preventing foot slap at loading response. Peroneus longus aids in stabilizing the foot and arch, not the main plantarflexion control here.

During loading response, the ankle moves from heel strike into controlled plantarflexion as weight is borne. The key to preventing foot slap is the dorsiflexor group contracting eccentrically to slow this plantarflexion. The tibialis anterior lengthens under tension while it still contracts to pull the foot into dorsiflexion, acting as a brake on sudden plantarflexion. If this eccentric dorsiflexor control is lacking, the foot can drop and slap the ground.

Gastrocnemius and soleus are plantarflexors themselves and contribute to control in other phases, but they’re not the primary eccentric brake preventing foot slap at loading response. Peroneus longus aids in stabilizing the foot and arch, not the main plantarflexion control here.