Bilateral and unilateral load-velocity profiling in a machine-based, single-joint, lower body exercise.

Abstract

BackgroundTo analyze the goodness of fit of the load-velocity relationship in a machine-based, single-joint exercise performed both in a bilateral and unilateral manner, as well as to study its accuracy to estimate one repetition maximum (1-RM).MethodsFifteen resistance trained males performed an incremental test in the bilateral and unilateral leg extension exercise up to the 1-RM in two separate occasions. Mean vertical velocity of the weight plates in the leg extension machine was measured for every repetition using a smartphone application (My Lift).ResultsLinear regression analyses showed a high goodness of fit (R2 > 0.93) and small standard errors of estimate (SEE 1.0, p 0.05).ConclusionsThis proof of concept highlights that computing load-velocity relationships in a machine-based, single-joint, angular exercise can be appropriately performed by measuring the mean vertical velocity of the weight plates. These results could help strength and conditioning researchers and coaches who wish to analyze load-velocity relationship in other common machine-based exercises.