Question

Which phase(s) of gait does tibialis anterior eccentrically control ankle plantar flexion during gait? (select all that apply).

A) Initial contact.
B) Loading response.
C) Mid-stance.
D) Terminal stance.
E) Pre-swing.

Answer 1

The tibialis anterior muscle eccentrically controls ankle plantar flexion during initial contact and loading response phases of the gait cycle, helping to lower the foot gently and maintain balance and stability. The options (A) and (B) are correct.

Step-by-step explanation:

The tibialis anterior muscle is responsible for dorsiflexion of the foot at the ankle joint, and it also helps to control plantar flexion eccentrically. During the gait cycle, the tibialis anterior eccentrically controls ankle plantar flexion in two key phases:

• Initial contact: At this point, the foot is beginning to touch the ground, and the tibialis anterior contracts eccentrically to control the rate of plantar flexion, helping to gently lower the foot.
• Loading response: Immediately after initial contact, weight is transferred onto the leading leg. Here, the tibialis anterior continues to control plantar flexion eccentrically, allowing the foot to adapt to the surface and bear the body's weight smoothly.

The muscle action during these phases prevents the foot from slapping down onto the ground and helps maintain balance and stability at the beginning of the stance phase of the gait cycle. Although the tibialis anterior is still active in the subsequent phases of the gait cycle, its primary role in controlling plantar flexion eccentrically is during the initial contact and loading response phases. Therefore, options (A) and (B) are correct.