Is the Rear Foot Elevated Split Squat Unilateral? An Investigation Into the Kinetic and Kinematic Demands.

ABSTRACT: Helme, M, Emmonds, S, and Low, C. Is the rear foot elevated split squat unilateral? An investigation into the kinetic and kinematic demands. J Strength Cond Res 36(7): 1781-1787, 2022-The purpose of the study was to determine the unilateral nature of the rear foot elevated split squat (RFESS). Specifically, the production of force by the rear leg was examined to better understand its role, if any, toward successful completion of the exercise. Male volunteers were recruited (n = 26, age = 23.8 ± 4.6 years, body mass = 88.1 ± 10.7 kg, and height = 1.79 ± 0.1 m), who were recreationally trained and engaged in a structured strength and conditioning program, including both bilateral and unilateral exercises, and had at least 2 years supervised training experience. Subjects participated in an incremental 5 repetition maximum protocol after familiarization. Kinetic data were recorded through 2 independent force plates, 1 integral to the floor and the second mounted on top of solid weightlifting blocks. Kinematic data were captured through 3-dimensional motion analysis. A total of 715 repetitions were analyzed, and the mean contribution of the lead foot to total vertical force production was 84.36 ± 3.6%. An almost certainly small positive correlation (rho = 0.25, confidence interval [CI] 0.18-0.33) was found between the percentage of force produced by the lead foot, with increasing exercise intensity. A most likely trivial, nonsignificant correlation (rho = -0.01, CI -0.09 to 0.06) with rear foot force production, representing the mass of the rear leg. Data from this study do not indicate that the rear foot contributes to the kinetic demands of the exercise and therefore suggests that the RFESS is a valid unilateral exercise.