Immediate Effect of Restricted Knee Extension on Ground Reaction Force and Trunk Acceleration during Walking

Abstract

Gait parameters calculated from trunk acceleration reflect the features of gait; however, they cannot evaluate the gait pattern corresponding to the gait cycle. This study is aimed at investigating the differences in gait parameters calculated from trunk acceleration during gait corresponding to the gait cycle in healthy subjects with restricted knee extension. Participants included eight healthy volunteers who walked normally (NW) and with knee orthosis that restricted knee extension (ER). The ground reaction force (GRF), joint angles, and trunk acceleration during walking were measured using four force plates, a three-dimensional motion analysis system, and an inertial measurement unit. The peak GRF of the vertical components, joint ranges of motion, and moments of force were analyzed. The root mean square (RMS) and amplitude peak ratio (AR) of autocorrelation function were calculated from the trunk acceleration waveform. The first peak GRF and peak ankle dorsiflexion angles significantly increased during ER. The peak hip extension, knee flexion, knee extension angles, and the peak moment of knee extension significantly decreased during ER compared to that during NW. The acceleration AR significantly decreased during ER compared to that during NW. There was no significant difference in the RMS between the two conditions. The acceleration AR may show the temporal postural structure with restricted knee extension from the terminal stance phase for the ipsilateral limb to the initial stance phase for the contralateral limb. These results suggest that novel metrics for accelerometry gait analysis can reveal gait abnormalities, with restricted knee extension corresponding to the gait cycle.

Effects of Artificially Induced Leg Length Discrepancy on Treadmill-Based Walking and Running Symmetry in Healthy College Students: A Lab-Based Experimental Study

“…Knee joint restriction, which is expected to be encountered in the gait cycle of individuals with LLD where the longer leg tends to shorten during the stance phase, may eventually increase the ground reaction forces exerted, especially on the midfoot area of the LLS. Previous studies indirectly confirm our observations as they have shown that similar artificially induced restrictions in the knee joint flexion (or extension) increase peak ground reaction forces during walking [61,62]. These changes have been observed in both the limb with restricted and the contralateral limb with unrestricted movement of the knee joint at distinct phases of gait, although significant differences were found only for initial contact [61].…”

“…Previous studies indirectly confirm our observations as they have shown that similar artificially induced restrictions in the knee joint flexion (or extension) increase peak ground reaction forces during walking [61,62]. These changes have been observed in both the limb with restricted and the contralateral limb with unrestricted movement of the knee joint at distinct phases of gait, although significant differences were found only for initial contact [61]. The fact that the GRFs exerted on midfoot areas of both feet were progressively increased as LLD increased may also be related to the greater pronation and supination expected to be presented by the LLS and SLS foot, respectively, during walking [33], as has been shown in individuals with asymptomatic pronated and supinated feet [63].…”

Effect of Unilateral Knee Extension Restriction on the Lumbar Region during Gait

“…Kinetic changes during walking with a restricted extension of the knee joint have been analysed in previous studies where knee joint force was bilaterally increased during loading response depending on the degree of restriction of the knee joint [11][12][13]. Knee extension restriction also increases the vertical component of ground reaction force and the external knee flexion moment, which increases the demand for muscle activity in the lower extremities [14][15][16][17]. Gait kinematics and kinetics due to restriction of knee extension might increase the load on the lumbar region during the loading response phase of the restricted lower limb during gait and is related to low back pain.…”