Countermovement Jump Analysis Using Different Portable Devices: Implications for Field Testing

Vincenzo Rago,António Rebelo,Thiago Carvalho,João Brito,Tiago Fernandes,Pedro Figueiredo,Pedro Fonseca

doi:10.3390/sports6030091

Vincenzo Rago, António Rebelo + Show 5 more

Open Access

https://doi.org/10.3390/sports6030091

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Abstract

The aim of this study was to analyze the concurrent validity, test–retest reliability, and capacity to detect changes of four different portable devices used to measure a wide range of neuromuscular parameters derived from countermovement jump (CMJ). An accelerometric device (Myotest), a jump mat (Ergojump), an optical device (Optojump), and a smartphone app (MyJump) were simultaneously examined for concurrent validity against gold-standard measures (motion-capture system and a force platform). Twenty-two CMJ-derived variables were collected from 15 healthy male subjects (n = 60 CMJs). Contraction time (CT) and eccentric duration (EccD) measurements obtained from the Myotest were moderately to largely associated with and not different from force platform measurements (r = 0.31 to 0.64, ES = 0.11 to 0.18) and showed moderate test-retest reliability (intraclass correlation coefficient (ICC) = 0.92 to 0.97, coefficient of variation (CV) = 3.8 to 8.0%). Flight time (FT) and jump height (JH) from Ergojump, Optojump, and MyJump showed moderate to strong associations with gold-standard measurements (r = 0.57 to 0.98) and good test–retest reliability (ICC = 0.54 to 0.97, CV = 1.8 to 4.2). However, all portable devices underestimated JH (ES = 1.25 to 2.75). Independent of the instrument used, the analyzed CMJ variables showed good capacity to detect changes (standard error of measurement (SEM) < smallest worthwhile change (SWC)), with the exception of rate of force and rate of power development parameters, which showed marginal capacity (SEM > SWC). The Myotest is preferable to measure temporal parameters during ground contact, whereas Ergojump, Optojump, and MyJump devices may be preferable to measure FT and JH, with the Optojump being the most accurate.

Highlights

The countermovement jump (CMJ) is one of the most popular tests to monitor an athlete’s muscle power of the lower extremities
This study compares a wide range of CMJ-derived variables over six different devices, aiming to analyze the most convenient tool to be employed for on-field neuromuscular testing
The portable devices showed different levels of accuracy to measure CMJ according to the specific neuromuscular parameters analyzed, Myotest should be preferred to measure CMJ-derived temporal parameters during ground contact (e.g., Contraction time (CT) and eccentric duration (EccD))

Summary

Introduction

The countermovement jump (CMJ) is one of the most popular tests to monitor an athlete’s muscle power of the lower extremities. JH significantly dropped in response to recreational 5v5 small-sided soccer games [6], whereas CMJ height was not altered following 4v4 and 8v8 small-sided soccer games [7] Taken together, these findings indicate that JH or FT per se does not elucidate an eventual mask over acute fatigue responses or over chronic adaptations to exercise. These findings indicate that JH or FT per se does not elucidate an eventual mask over acute fatigue responses or over chronic adaptations to exercise In this context, critical information can be directly extracted from the force–time curves during the CMJ, and various parameters (e.g., contraction duration, time to peak force/power) have been recently deemed suitable for neuromuscular fatigue detection.

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