Knee flexion at strike
How bent the knee is at the instant the foot first touches the ground.
Why it matters
A straighter knee at landing means less muscle available to absorb shock, which pushes more force straight up the shin — a common precursor to bone stress injuries.
What it means
A bent knee (around 140–155°) at strike absorbs impact. A near-straight knee (>165°) signals overstride and a high vertical loading rate. This metric is closely linked to overstriding: reducing overstride by shortening your stride and increasing cadence typically increases knee flexion at strike automatically.
Related reading
The complete guide to running form analysis