Which direction is the horizontal ground reaction force pointed at heel contact?

Which direction is the horizontal ground reaction force pointed at heel contact?

• A. Medially
• B. Posteriorly
• C. Anteriorly
• D. Laterally

Answer: (B)

During heel contact in gait, the horizontal component of the ground reaction force is directed backward. This braking force arises because the body is moving forward as the foot lands, and the ground must push back on the foot to slow that forward progress and help control the initial impact and leg motion. The backward (posterior) force aids in stabilizing the knee and preparing the limb for the following stance phases. The anterior-directed force occurs later, during push-off, when the aim is propulsion rather than braking. Medial or lateral directions are not the primary horizontal component at heel contact, which is why posteriorly is the correct direction.

During heel contact in gait, the horizontal component of the ground reaction force is directed backward. This braking force arises because the body is moving forward as the foot lands, and the ground must push back on the foot to slow that forward progress and help control the initial impact and leg motion. The backward (posterior) force aids in stabilizing the knee and preparing the limb for the following stance phases. The anterior-directed force occurs later, during push-off, when the aim is propulsion rather than braking. Medial or lateral directions are not the primary horizontal component at heel contact, which is why posteriorly is the correct direction.