Hip Extension at Push-Off

Why this matters

Hip extension is the prime mover of forward propulsion. At toe-off, the gluteus maximus pulls the thigh back behind the body — that's what pushes the runner forward. A limited extension at toe-off (5° or less) caps top speed and shortens stride length; the runner has to compensate by pumping the arms harder or leaning the trunk forward, both of which are mechanically expensive.

The angle is doubly diagnostic. What it shows directly: how far the thigh travelled back through the stance phase. What it implies: whether the glute fired in time to drive the push-off, whether the hip flexors are tight enough to limit it, and whether the lumbar spine is being recruited as a substitute. Tight hip flexors on the trailing leg — extremely common in desk-job runners — cap hip extension and force the lumbar spine into compensatory extension (an arched-back look). That trades smooth propulsion for sustained spinal load.

What good looks like

At toe-off the thigh leans 10–20° behind vertical. The torso stays close to upright — no compensatory backward lean. The trailing knee follows the thigh smoothly through the extension and starts to flex as the leg enters recovery.

Common faults

• Stiff hip (≤5° extension) — common in runners with tight hip flexors or under-active glutes. Looks like a "shuffling" stride from the side. Top-speed ceiling.
• Compensatory lumbar extension — the lumbar arches to make up for the limited thigh travel. Often paired with anterior pelvic tilt. Loads the lower back instead of the hip.
• Excessive extension (>25°) — rare; usually a hypermobile athlete. Risk is anterior hip impingement and labrum stress over time.

Coaching cues

• "Squeeze the glute at toe-off." Conscious cue, paired with strength work (hip thrusts, single-leg deadlifts).
• Hip flexor mobility: kneeling lunge stretches, daily, before runs.

Related measurements

• Stride Angle at Push-Off — measured at the same frame; the trailing tibia angle is the visible signature of the hip extension.
• Midstance Knee Flexion — the upstream phase. A collapsed knee at midstance often pairs with limited hip extension at toe-off (the leg drives the wrong way).