Form fundamentals
Knee Flexion at Midstance
How deep the knee loads when your body passes over the planted foot (~40° is ideal).
What it is
At midstance your knee compresses to its deepest stance angle — the loaded-spring position. Around 40° of flexion stores and returns energy; much less is a stiff stride, much more is a collapsing one.
Why it matters
Too little midstance bend can't absorb impact (it shows up as bounce and joint stress); too much means the quads and glutes can't support the load — a strength flag more than a technique flag.
How we detect it
We find the frame where your ankle passes under your hip in each stance and measure knee flexion there, median across strides, per leg.
How to fix it
A stiff midstance usually rides along with overstriding — fix contact first. A collapsing midstance responds to single-leg strength: split squats, step-downs, hill strides.
Recommended drills
- •Bulgarian split squats (3x10/side)
- •Single-leg squats to a box (3x8/side)
- •Plyo hops (3x20)
Run these 2-3x per week. Expect to feel a change in form 4-6 weeks in.