Form fundamentals
Ground Contact Time
How long each foot spends on the ground, and whether left and right match.
What it is
The milliseconds between initial contact and toe-off. Shorter contacts (with real flight time between them) mean a springier, more elastic stride. We also compare left vs right — persistent imbalance is an injury flag.
Why it matters
Contact time correlates strongly with running economy at a given pace, and contact-time asymmetry above a few percent is one of the metrics sports-med clinics track for return-to-run decisions.
How we detect it
We detect each stance from your foot trajectory with sub-frame timing, take the median per leg, and report the left/right balance. Precision is caveated on low-fps video — 60 fps clips sharpen it.
How to fix it
Contact time follows cadence and stiffness: metronome work plus pogo hops and rope skipping build the elastic qualities that shorten contacts naturally. Don't chase the number at the cost of a shuffle.
Recommended drills
- •Metronome runs at +5% cadence
- •Double-leg pogo hops (3x20)
- •Rope skipping (3x60s)
Run these 2-3x per week. Expect to feel a change in form 4-6 weeks in.