Drop Jump

Reactive strength. RSI = jump height / ground contact time. Stiffness of the triceps surae complex.

Run in Capture Lab

Setup

Box 30 cm unless a drop-height profile is being collected
Step off — do not jump up off the box
Cue: 'spend as little time on the ground as you can'

Scoring rubric

RSI ≥ 1.5 is a common field benchmark (task- and population-specific)
Contact time typically 0.15–0.25 s for a true bounce strategy
Knee flexion on contact stays modest — a deep dip is a CMJ, not a DJ

Literature

Flanagan & Comyns 2008; Pedley et al. 2017 — RSI utility and strategy distinction.

Tracked joints: ankle, knee, COM. The kinematic engine is a teaching model scaled to the active subject. Export CSV from the report for your own processing.