Lower Limb Movement Symmetry Cannot Be Assumed When Investigating the StopJump Landing

EDWARDS, SUZI1; STEELE, JULIE R.2; COOK, JILL L.3; PURDAM, CRAIG R.4; McGHEE, DEIRDRE E.2

Medicine & Science in Sports & Exercise: June 2012 - Volume 44 - Issue 6 - p 1123–1130
doi: 10.1249/MSS.0b013e31824299c3
Applied Sciences

Purpose: When investigating lower limb landing biomechanics, researchers often assume movement symmetry between a participant’s right and left lower limbs for the simplicity of data collection and analysis, although landing tasks often involve dual-limb motion. However, whether lower limb symmetry can be assumed when investigating dynamic, sport-specific movements such as the stop–jump has not been investigated. Therefore, this study aimed to determine whether there were any significant differences in selected kinetic, kinematic, and muscle activation patterns characterizing lower limb biomechanics displayed by the dominant limb compared with the nondominant limb of participants during a stop–jump task.

Methods: Sixteen male athletes with normal patellar tendons on diagnostic imaging performed five successful stop–jump trials. Patellar tendon forces (FPT), ground reaction forces, three-dimensional kinematics, and EMG activity of seven lower limb muscles were recorded for the dominant and nondominant lower limbs during each trial.

Results: During the horizontal landing phase, the dominant lower limb sustained a significantly higher FPT and peak net knee joint extension moment compared with the nondominant lower limb. Furthermore, during the vertical landing phase, the dominant lower limb sustained significantly lower vertical but higher posterior ground reaction forces compared with the nondominant lower limb. Other variables did not significantly vary as a function of lower limb dominance.

Conclusions: It is recommended that researchers clearly identify their primary outcome variables and ensure that their experimental design, particularly in terms of lower limb dominance, provides an appropriate framework to investigate possible mechanics underlying unilateral and bilateral knee joint injuries during dual-limb movements such as the stop–jump task.

1School of Human Movement Studies, Charles Sturt University, New South Wales, Australia, AUSTRALIA; 2Biomechanics Research Laboratory, University of Wollongong, New South Wales, Australia, AUSTRALIA; 3Department of Physiotherapy, Monash University, Clayton, Victoria, AUSTRALIA; and 4Australian Institute of Sport, Canberra, Australian Capital Territory, AUSTRALIA

Address for correspondence: Suzi Edwards, Ph.D., M.Sc., B.App.Sc., School of Human Movement Studies, Charles Sturt University, Panorama Ave, Bathurst, NSW 2795, Australia; E-mail: suzedwards@csu.edu.au.

Submitted for publication August 2011.

Accepted for publication November 2011.

©2012The American College of Sports Medicine