Form fundamentals
Knee Mechanics
Knee flexion at stance — too straight means braking, too bent means quad-dominant.
What it is
The angle at your knee at the moment of foot contact and through stance phase. Too straight (>165°) and you're not absorbing impact. Too bent (<140°) and your quads are doing the work your glutes should be.
Why it matters
Knee mechanics tie directly into overstriding (straight-leg landings) and posture (collapsing hinge). Most runner's knee (PFPS) and patellar tendinopathy traces back here.
How we detect it
We compute the angle formed by hip → knee → ankle across the whole video and average it. We also flag asymmetries between left and right knees.
How to fix it
If your average knee angle is too straight, you're overstriding — fix that first. If your knees are too bent, you need stronger glutes to share load with the quads. Posterior chain work pays dividends here.
Recommended drills
- •Bulgarian split squats (3x10/side)
- •Terminal knee extensions with band (3x15)
- •Step-downs (3x10/side, slow eccentric)
Run these 2-3x per week. Expect to feel a change in form 4-6 weeks in.