How accurate is the Plyomat jump mat?

To check how closely the mat reads, Plyomat jump heights were compared against an AccuPower force plate as the reference, the same kind of equipment a sports-science lab trusts. The work used 48 Division III athletes at Springfield College, each jumping on the mat and the plate so the two readings could be lined up directly.

Across those athletes the agreement was strong: a correlation of r ≈ 0.97, an ICC of 0.85, and a mean difference of about 1 cm in jump height. In coaching terms, when the force plate said an athlete jumped a given height, the Plyomat was right there with it, within roughly a centimeter on average.

This page presents the headline figures and an honest methods note. Full methods, the Bland-Altman limits-of-agreement, and the exact protocol are available on request. We would rather under-claim and let you check the detail than dress up a single number.

r ≈ 0.97 is the agreement. Correlation runs from 0 (no relationship) to 1 (perfect). At 0.97 the mat and the force plate move together almost in lockstep: a higher jump on the plate is a higher jump on the mat, with very little scatter between them.

ICC 0.85 is the reliability. The intraclass correlation coefficient asks a stricter question than plain correlation: do the two methods produce the same value, not just the same ranking? An ICC of 0.85 is generally read as good-to-strong reliability, which is what you want from a tool you will use to track athletes session after session.

~1 cm is the typical gap. On average the mat and the plate landed within about a centimeter of each other. That is the everyday error to keep in mind when you read a result, and it is small relative to the changes you are usually trying to detect in training.

Validated means close agreement, not identical. A force plate measures force directly and stays the laboratory reference. A contact mat infers jump height from flight time. So the right standard is agreement within known bounds, and that is exactly what r ≈ 0.97, ICC 0.85, and a ~1 cm mean difference describe. We do not claim Plyomat beats a force plate or an optical system.

Elite jumpers above 0.70 m are the known caveat. Contact mats can underestimate flight time, and therefore jump height, for athletes with very long flight times (above about 0.70 m). For that smaller group, expect the mat to read slightly low rather than high. Plyomat's real value is consistency and repeatability for tracking the same athletes over time, backed by strong force-plate agreement in the normal jumping range.

A ~1 cm offset is the expected band, not a flaw. Even lab-grade optical systems carry an offset of their own: Optojump sits about -1.06 cm versus a force plate. So a field tool agreeing within roughly a centimeter is a credible, expected result, not a sign something is off. Use any single tool consistently and you will trust the trend.