Comparison of Ground Reaction Force Asymmetry in One- and Two-legged Countermovement Jumps

Abstract

This study examined whether ground reaction force (GRF) asymmetry of 2-legged countermovement jumps (CMJ) is related to 1-legged CMJ asymmetry. The GRF asymmetry of a 2-legged CMJ has been suggested as a preferred test to the 1-legged CMJ for functional strength and power deficit assessment. Twenty-eight men and 30 women performed 5 trials each of a 1-legged CMJ with the right limband the left limb, and a 2-legged CMJ. Vertical GRFs were collected from each lower limb using 2 force platforms. Although several GRF variables were calculated, vertical impulse correlated most strongly with jump height in all conditions (p < 0.05), and they were used in subsequent analyses. A moderate correlation was found for impulse asymmetry between the 1- and 2-legged CMJs for women (r = 0.45, p < 0.05), but not for men (r = 0.06, p = 0.76). In contrast, cross-tabulation analyses of subjects presented with the same dominant characteristics in the 1- and 2-legged CMJs revealed poor associations for both men (Freeman-Halton exact p = 0.61) and women (Freeman-Halton exact p = 0.19). Only 11 women recorded the same dominant limb for both 1- and 2-legged CMJs. This suggests that impulse asymmetries found in the 1- and 2-legged CMJ were unrelated. As the 1-legged CMJ relies on the extension forces generated entirely from 1 limb, variations in jump heights and GRF impulses by left and right limbs separately were more indicative of functional strength differences between sides. Hence, it is recommended that the 1-legged CMJ is used when examining functional strength asymmetry in the lower limbs. In contrast, factors causing asymmetry in GRF impulses during 2-legged CMJs are more complicated and require further investigation.

A comparison of methods to determine bilateral asymmetries in vertical leg stiffness

“…For example, an individual may demonstrate greater K vert in the right limb during the bilateral drop jump but greater K vert in the left limb during the unilateral drop jump. Benjanuvatra et al (2013) reported similar findings for vGRF impulse asymmetries during bilateral and unilateral countermovement jumping, hypothesising that asymmetries during the bilateral jump were governed by a neural control mechanism in agreement with previous conclusions drawn by Simon and Ferris (2008). Ultimately, unilateral jumping performance is reliant solely on the forces transferred and generated through a single limb as opposed to an inter-limb "tradeoff" that is apparent during bilateral jumping.…”

Lean Mass Asymmetry Influences Force and Power Asymmetry During Jumping in Collegiate Athletes

“…However, bilateral tasks are becoming increasingly common in an attempt to evaluate injury risk (12) and the relative contribution of each limb is best evaluated using instrumented testing devices such as force platforms. In fact, previous research has concluded that the best predictor of vertical jump height is power normalized to body weight (19) or vertical impulse (2). Recent research has also observed poor association between asymmetries between double- and single-leg CMJs which suggests that both tasks are important for identification of asymmetry (2).…”

“…For example, Impellizzeri et al (14) measured ground reaction forces bilaterally during a countermovement jump (CMJ) in 313 male soccer players and observed an average asymmetry of 6%. While higher levels of asymmetry (10%) were observed in a physically active, but not highly trained, population (2). Further, the asymmetry in force during jumping was correlated with strength asymmetry, as measured by isometric leg press (r = .83) and isokinetic concentric knee extension torque (r = .48) (14).…”

“… The purpose of this investigation was to: (1) examine how asymmetry in lower extremity lean mass influenced force and power asymmetry during jumping, (2) determine how power and force asymmetry affected jump height, and (3) report normative values in collegiate athletes. Force and power were assessed from each limb using bilateral force plates during a countermovement jump in 167 Division 1 athletes (mass=85.7±20.3kg, age=20.0±1.2years, 103M/64F).…”

The effects of strength training on isometric force production symmetry in recreationally trained males

“…1,2 Specifically, the relationships between force production symmetry, injury, and performance seem to be a common interest. [3][4][5] The lack of ability to produce symmetrical movement patterns and the inability to produce force symmetrically have been indicated as risk factors for injury, but currently there remains some doubt due to a lack of direct evidence to support this claim.…”