Weakening iliopsoas muscle in healthy adults may induce stiff knee pattern

Abstract

Objective: To investigate the relation between iliopsoas muscles weakness and related hip-joint velocity reduction and stiff knee gait (SKG) during walking in healthy individuals. Design: Design: In 15 neurologically intact able-bodied participants (average age: 22.4 ± 0.81 years), a load 5% of each individual's body weight was placed on the non-dominant thigh. For 33 min (135sec x 13 repetitions x 5sec rest), a passive stretch (PS) was applied with the load until the hip-flexor muscle strength dropped from 5/5 to 3+/5 according to the manual muscle test. All the participants underwent gait analysis before and after the PS to compare sagittal plane hip knee and ankle kinematics and kinetics and temporo-spatial parameters. The Paired-T test was used to compare pre and post stretching findings and the Pearson correlation coefficient (r) was calculated to determine the strength of the correlation between SKG parameters and interested gait parameters (p<0.05). Results: Reduced hip-flexion velocity (mean, 21.5%, p = 0.005) was one of the contributors of SKG that acted by decreasing the peak knee flexion (PKF) (-20%, p = 0.0008), total knee range (-18.9%, p = 0.003), and the range of knee flexion between toe-off and PKF (-26.7%, p = 0.001), and by shortening the duration between toe-off to PKF (-16.3%, p = 0.0005). Conclusions: Conclusions: These findings verify that any treatment protocol that slows hip-flexion during gait by weakening the ilio-psoas muscle may have a great potential to produce an SKG pattern combined with reducing gait velocity. DOI: 10.3944/AOTT.2016.15.0406 This abstract belongs to the un-edited version of the article and is only for informative purposes. Published version may differ from the current version.