Resumen de Criterion Validity of a MARG Sensor to Assess Countermovement Jump Performance in Elite Basketballers

Craig A. Staunton, Jonathan J. Stanger, Daniel W. Wundersitz, Brett A. Gordon, Edhem Custovic, Mike I.C. Kingsley

• This study assessed the criterion validity of a magnetic, angular rate, and gravity (MARG) sensor to measure countermovement jump (CMJ) performance metrics, including CMJ kinetics before take-off, in elite basketballers. Fifty-four basketballers performed 2 CMJs on a force platform with data simultaneously recorded by a MARG sensor located centrally on the player's back. Vertical accelerations recorded from the MARG sensor were expressed relative to the direction of gravity. Jumps were analyzed by a blinded assessor and the best jump according to the force platform was used for comparison. Pearson correlation coefficients (r) and mean bias with 95% ratio limits of agreement (95% RLOA) were calculated between the MARG sensor and the force platform for jumps performed with correct technique (n = 44). The mean bias for all CMJ metrics was less than 3%. Ninety-five percent RLOA between MARG- and force platform-derived flight time and jump height were 1 +/- 7% and 1 +/- 15%, respectively. For CMJ performance metrics before takeoff, impulse displayed less random error (95% RLOA: 1 +/- 13%) when compared with mean concentric power and time to maximum force displayed (95% RLOA: 0 +/- 29% and 1 +/- 34%, respectively). Correlations between MARG and force platform were significant for all CMJ metrics and ranged from large for jump height (r = 0.65) to nearly perfect for mean concentric power (r = 0.95). Strong relationships, low mean bias, and low random error between MARG and force platform suggest that MARG sensors can provide a practical and inexpensive tool to measure impulse and flight time-derived CMJ performance metrics.