The influence of balance support base manipulation on the kinematics of lower limbs during single-legged squats in people with patellofemoral pain

Background: Given that people with patellofemoral pain (PFP) exhibit deficits in postural control, certain postural reactions may be associated with movement alterations in this population. Therefore, the objective of the present study was to investigate whether manipulation of the support base for balance maintenance could lead to different patterns of lower limb kinematics in people with PFP during single-legged squats.

Methods: Fourteen participants with PFP and 14 asymptomatic controls were first assessed performing single-legged squats freely, and then while holding a stick to provide stabilization during the task. Center of pressure (CoP) behavior and movements of the hip, knee, ankle in the sagittal, frontal, and transverse planes were evaluated.

Results: For the participants with PFP, the use of support led to a reduction in the magnitude of CoP oscillation compared to free squatting, with effect sizes ranging from small to large, but no significant differences were found for the kinematic variables. No significant differences were observed for CoP or kinematic variables in the comparisons between squat conditions in asymptomatic controls.

Conclusion: In summary, performing single-legged squats in a more stabilized condition did not influence lower limb movements in people with PFP.