How the Coil-Cushion Index works (exploratory footwear-testing tool)
CCI v1 combines three equally weighted signals: greater stiffness divided by body weight, shallower squat depth, and shorter braking time. Each is converted to a 0–100 percentile against this roster's Non-Conference tests, with each athlete weighted equally. Depth and braking-time percentiles are reversed, then all three are averaged. The same reference is used throughout the season; missing or non-positive inputs produce no score.
Cushion ≤40: deeper / longer-loading strategy. Hybrid >40 to 60: middle range. Coil >60: compact / quick-loading strategy. Labels use each athlete's average score in the selected destination phase, not a permanent athlete identity. These cutoffs and equal weights are provisional, not validated. The inputs overlap biomechanically; they are not three independent proofs of elasticity.
Use profiles to stratify matched shoe crossover tests. Coil: compare forefoot responsiveness and stability. Cushion: compare controlled compression and platform support. Hybrid: compare balanced setups. Measure jump performance, comfort, landing force and asymmetry separately in every profile. The index does not measure tendon elasticity, shoe energy return, injury risk, or prove that a shoe works. Higher is not better; “Cushion” describes takeoff strategy, not softer landings.
Score changes are shown in points, not percent. CCI tests have their own exploratory FDR family, preserving the original metrics' statistical results. Correlations with its ingredients partly reflect the formula. The spreadsheet includes the reference distribution and athlete-phase score means.