During push-off, minor activity of EDL and EHL may provide ankle stability through coactivation with which muscles?

During push-off, minor activity of EDL and EHL may provide ankle stability through coactivation with which muscles?

• A. Hip abductors
• B. Knee flexors
• C. Hip extensors
• D. Ankle plantar flexors

Answer: (C)

Coactivation across joints helps stabilize the leg during push-off, not just the ankle moving in isolation. The small activity of the toe and foot extensors (EDL and EHL) can contribute to keeping the ankle stable by working in concert with proximal stabilizers. The hip extensors play a key role here: as they contract to extend the hip, they help control the position of the pelvis and trunk, which in turn reduces unwanted tibial movement and keeps the ankle aligned as propulsion begins. This proximal stability allows the distal muscles to manage toe-off without letting the ankle slip into instability. The other options don’t fit as well. Hip abductors mainly stabilize the pelvis in the frontal plane, which is less about the sagittal stability needed during push-off. Knee flexors would oppose the straight-legged propulsion pattern typical of push-off and aren’t the primary stabilizers for the ankle in this moment. Ankle plantar flexors drive the push-off themselves, so coactivation with them isn’t the mechanism here.

Coactivation across joints helps stabilize the leg during push-off, not just the ankle moving in isolation. The small activity of the toe and foot extensors (EDL and EHL) can contribute to keeping the ankle stable by working in concert with proximal stabilizers. The hip extensors play a key role here: as they contract to extend the hip, they help control the position of the pelvis and trunk, which in turn reduces unwanted tibial movement and keeps the ankle aligned as propulsion begins. This proximal stability allows the distal muscles to manage toe-off without letting the ankle slip into instability.

The other options don’t fit as well. Hip abductors mainly stabilize the pelvis in the frontal plane, which is less about the sagittal stability needed during push-off. Knee flexors would oppose the straight-legged propulsion pattern typical of push-off and aren’t the primary stabilizers for the ankle in this moment. Ankle plantar flexors drive the push-off themselves, so coactivation with them isn’t the mechanism here.