RPeM: a smartphone-derived index of concentric propulsive efficiency in university athletes. An exploratory cross-sectional analysis
DOI:
https://doi.org/10.47197/retos.v83.119004Keywords:
Concentric phase, exploratory index, mixed-effects model, propulsive efficiency, smartphone assessment, vertical jumpAbstract
Background. Vertical jump height does not capture the time over which propulsive force is produced. This study introduces RPeM (Relative Propulsive efficiency Metric), an exploratory index relating jump height to concentric time in university athletes. RPeM is descriptive and is not proposed as a measure of fatigue, readiness, or injury risk.
Methods. 349 university athletes (216 men, 133 women) performed SJ, CMJ, and CMJFree, assessed with My Jump Lab at 240 fps; 567 observations were retained after quality-control and best-attempt selection. RPeM (jump height ÷ concentric time; cm·s⁻¹) was analysed with a log-transformed linear mixed model (jump type, sex, and sport as fixed effects; athlete as random effect); non-parametric tests served as sensitivity checks.
Results. The model explained substantial variance (marginal R² = 0.324; conditional R² = 0.960). RPeM differed by modality (F₂,₁₉₅ = 300.18, p < .001, η²p = 0.755), sex (F₁,₃₂₇ = 75.67, p < .001, η²p = 0.188), and sport (F₆,₄₀₈ = 7.42, p < .001, η²p = 0.098). Estimated marginal means increased from SJ (94.3) to CMJ (111.0) to CMJFree (132.6 cm·s⁻¹) and were higher in men (135.5) than women (91.8).
Conclusions. RPeM behaves coherently across modalities and sex but shares 60–70% of its variance with jump height (r = 0.78–0.84), largely re-expressing the variable from which it is derived. It is an exploratory, transparent descriptor requiring further evaluation before applied use; the readiness output showed zero variance and could not be analysed.
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Copyright (c) 2026 Cristian Alexis Lasso-Quilindo, Carlos Manuel Chacón-Rodríguez, José Raúl Hoyos-Flores, Giovani Camacho-Tristán, Omar Oswaldo Ayón-Barreras, Felipe Villegas, Pablo Tadeo Ríos Gallardo
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