Fibularis longus and brevis are active from approximately what portion of the gait cycle?

Fibularis longus and brevis are active from approximately what portion of the gait cycle?

• A. 70-100% only
• B. 0-5% only
• C. 5% to just before toe off
• D. Terminal swing only

Answer: (C)

The timing of fibularis longus and brevis activation is tied to their role in controlling foot stability during weight bearing and preparing for push-off. After heel contact, these muscles briefly start contracting to resist sudden inversion and to help progress the foot into stance, while also contributing to plantarflexion. They remain active through the majority of the stance phase, up to just before toe-off, when propulsion begins and other plantarflexors take over. This timing fits the need for lateral stabilization and controlled pronation as the body moves over the stance limb. The other options either truncate activation to a tiny moment or place it in phases (late swing or the entire swing) where these muscles aren’t functioning in weight-bearing, so they don’t best describe their usual activity pattern.

The timing of fibularis longus and brevis activation is tied to their role in controlling foot stability during weight bearing and preparing for push-off. After heel contact, these muscles briefly start contracting to resist sudden inversion and to help progress the foot into stance, while also contributing to plantarflexion. They remain active through the majority of the stance phase, up to just before toe-off, when propulsion begins and other plantarflexors take over. This timing fits the need for lateral stabilization and controlled pronation as the body moves over the stance limb. The other options either truncate activation to a tiny moment or place it in phases (late swing or the entire swing) where these muscles aren’t functioning in weight-bearing, so they don’t best describe their usual activity pattern.