Inter-individual variability in the load-velocity relationship isdetected by multilevel mixed regression models

Abstract

[Abstract]: The main aim of this study was to explore the variability in theload-velocity relationship through the use of multilevel mixedregression models. The relationship between relative load (% ofone repetition maximum: %1RM) and velocity was obtained ina sample of high-level judokas and rugby players (8 women and13 men) for the bench press (BP) and parallel squat (SQ). The load-velocity relationship for the squat was obtained for the externalload (barbell load) and for the system mass (barbell plus bodymass). The data were fitted by different multilevel mixed regres-sion models. Including the sex factor in the models improved thegoodness of fit for the BP but not for the squat exercises. All themodels detected significant inter-individual variability in bothintercepts and slopes (p < 0.05 in all the cases). A decrease of0.15, 0.10 and 0.16 m/s of velocity for each 10% of increment inthe relative load were estimated for BP and squat considering theexternal load and the system mass, respectively. The multilevelmixed regression models detected significant inter-individualvariability in the slope and intercept of the load-velocity relation-ship what entails differences in the velocity associated with a fixedpercentage (%) of the one-repetition maximum load.