RSI Calculator

RSI = jump height (m) ÷ contact time (s). For a Drop Jump, contact time is the real time spent on the ground between landing and rebounding. A CMJ has no landing phase, so "contact time" here means time-to-takeoff, the duration from the start of the countermovement dip to the feet leaving the ground — this variant is called RSI-modified and sits on a much lower numeric scale than Drop Jump RSI (roughly 0.2–0.7 versus 1–4+), so the two aren't directly comparable. The Developing-to-Elite tier badge only applies to Drop Jump RSI: there's no equally agreed-upon tier table for CMJ RSImod, partly because different testing devices don't all define "contact time" for a CMJ the same way. CMJ results still get a dot on the gauge below, but as a rough placement within the typical 0.2–0.7 range rather than a validated tier. Body weight is optional and only feeds Peak Power: it uses the Sayers equation (Sayers et al., 1999), the same estimate used on the Power Calculator page — a field-test approximation, not a lab measurement, most validated for an adult athletic population. The Casual-to-Olympian reference lines on the jump height chart are illustrative rather than a cited table — there's no single agreed mapping from competition level to jump height.