Trunk, hip and knee biomechanics in patellofemoral pain
A recent study has compared trunk muscle strength and activation levels, ipsilateral trunk lean, hip adduction and knee abduction during the single leg squat between subjects with and without PFPS. It was found that trunk strength was decreased in those with PFPS; no differences in activation levels were present between groups. On top of that, subjects with PFPS showed a greater ipsilateral trunk lean, hip adduction and knee abduction during the single leg squat.
It is generally accepted that kinematics of adjacent segments in the kinetic chain and linked anatomical structures can influence the biomechanics of the patellofemoral joint. Although it is often hypothesized that trunk and lower extremity movement patterns of subjects with patellofemoral pain syndrome (PFPS) during (single leg) weightbearing activities are alted, this mechanism is still incompletely described.
30 patients with PFPS and 30 controls matched for sex, age, height and bodyweight underwent an extensive testing procedure, including EMG assessment of the iliocostalis and external oblique abdominis muscles during both an isometric strength test as well as the single leg squat, and determining of the 3-D kinematics of the trunk, hip and knee.
As expected, trunk muscle strength was decreased in subjects with PFPS. Noteworthy, no difference in muscle activation levels was present between groups. Moreover, peak ipsilateral trunk lean, hip adduction and knee abduction during the single leg squat were increased in those with PFPS as compared with asymptomatic controls. Within the PFPS group, no associations were present between trunk muscle strength and activation levels and trunk, hip and knee kinematics.
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> From: Nakagawa et al., Man Ther 20 (2015) 189-193. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.