Leg Length Inequality Effects on Ground and Lower Extremity Joint Reaction Forces during Walking

Abstract

Leg length discrepancy (LLD) is caused either due to functional disorder or shortening of bone structure. This disorder could contribute to the significant effects on body weight distribution and lumbar scoliosis to a certain extent. Ground reaction force and joint reaction force are the parameters that can be used to analyse the responses in weight distribution and kinetics changes on the body joints, respectively. The purpose of this study was to determine the effect of Leg Length Discrepancy (LLD) on ground reaction force (GRF) and joint reaction force (JRF) in subjects mimicking LLD. Plywood block was used to mimic the artificial LLD. The height of the plywood was increased up to 4.0 cm with 0.5 cm increment. Hence, eight different height of LLD was considered to investigate which height of LLD initiated the significant effect. The experiment was conducted on ten healthy subjects that are walking on the force plate in two conditions; without load and with a load of 2 kg. Qualisys Track Manager (QTM) system and Visual 3D Software were employed for data processing. The result showed that mean peak vertical GRF and JRF of the shorter leg was found carried more weight than the longer leg during walking without load and walking with the additional load, respectively. Also, mean peak vertical GRF and JRF were found carried more weight during walking with additional load compared to walking without load.