Is there a correlation between isometric muscle strength and the kinematics of the pelvis, hip and knee during functional tasks in women with patellofemoral pain?

Abstract

ObjectivesTo evaluate the correlation between isometric muscle strength of the hip abductors (HABD) and lateral rotators (HLR) with the range of motion (ROM) of the pelvis/hip in the frontal/transverse planes, respectively, and between the strength of the knee extensors (KExt) with the ROM of the knee in the sagittal plane during seven tasks. DesignCross-sectional study. SettingLaboratory. ParticipantsThirty-five women with patellofemoral pain. Main outcome measuresMaximum isometric muscle strength of the HABD, HLR, and KExt was measured using a manual dynamometer, and pelvis and lower limbs kinematics were evaluated using 3D optical system during gait, ascending and descending stairs, the forward and lateral step down tests, and the propulsion and landing phases of the single leg hop test (SLHT). ResultsA weak correlation was found between KExt strength and knee ROM in the sagittal plane (p = 0.05; r = −0.33) during SLHT landing, and a moderate correlation between HABD strength and ROM of pelvic obliquity (p < 0.01; r = 0.50) during ascending stairs. ConclusionsThe lower strength of KExt has a weak correlation with higher knee flexion during the landing phase of the SLHT, and the lower strength of HABD has a moderate correlation with lower pelvis ROM in the frontal plane when ascending stairs.