Trunk and thigh coordination during a lateral step-down in athletes with patellofemoral pain

Research Objectives: To examine trunk-thigh coupling patterns and variability in athletes with patellofemoral pain and healthy controls.

Design: Cross-sectional design.

Setting: University research laboratory.

Participants: A convenience sample of 10 athletes with patellofemoral pain (6 females and 4 males) and 10 gender-matched healthy controls participated.

Interventions: All participants performed a repetitive lateral step down for one minute. The coupling pattern between the trunk and thigh were measured using the vector coding technique, based on the relative motion between the markers on the acromion process and lateral femoral condyle in the stance side. Trial-to-trial coupling variability was measured using the coefficient of correspondence.

Main Outcome Measures: The primary outcome variables were: (1) the coupling pattern between the distal trunk and the distal thigh in the test/stance side and (2) the variability of the coupling pattern in the test/stance side. These two variables were measured in two directions: contralateral-ipsilateral and anterior-posterior.

Results: We found a significant between-group difference in the coupling variability in the middle of the lateral step down (50% - 60% of the trial) in the contralateral-ipsilateral (left-right) direction. However, we did not find the coupling patterns to be different between the two groups.

Conclusions: The increased variability observed in the patellofemoral pain group could indicate a release of degrees of freedom to reduce repetitive loading at the same location on the structure.

Author(s) Disclosures: The authors declare that there is no conflict of interest.