During terminal stance and pre-swing, the GRF is positioned where relative to the hip axis?

During terminal stance and pre-swing, the GRF is positioned where relative to the hip axis?

• A. Far posterior to the axis
• B. Anterior to the axis
• C. Directly through the axis
• D. Medial only

Answer: (A)

During terminal stance and pre-swing, where the ground reaction force acts relative to the hip joint determines the external moment at the hip. In these late-stance phases, the line of action of the GRF moves behind the hip axis, meaning the force is far posterior to the hip joint. That posterior placement creates an external moment that tends to rotate the thigh into extension, aligning with the push-off progression of gait. The body then uses hip extensor control to coordinate this transition toward swing. If the force were in front of the axis, or directly through it, the resulting moments would be different and not characteristic of late stance.

During terminal stance and pre-swing, where the ground reaction force acts relative to the hip joint determines the external moment at the hip. In these late-stance phases, the line of action of the GRF moves behind the hip axis, meaning the force is far posterior to the hip joint. That posterior placement creates an external moment that tends to rotate the thigh into extension, aligning with the push-off progression of gait. The body then uses hip extensor control to coordinate this transition toward swing. If the force were in front of the axis, or directly through it, the resulting moments would be different and not characteristic of late stance.