Hip Kinematics During Single-Leg Tasks in People With and Without Hip-Related Groin Pain and the Association Among Kinematics, Hip Muscle Strength, and Bony Morphology.

The study is cross-sectional, so it cannot show whether hip weakness or movement changes came before pain, or whether changing them will improve symptoms. The pain group was heterogeneous: all had long-duration hip-related groin pain reproduced by FADIR, but FADIR is sensitive and not specific, and the source of pain may vary. No additional diagnostic imaging was done to identify labral tears or chondral lesions, so some participants may have had other hip pathology. Some participants had bony morphology features such as cam or pincer morphology or dysplasia, but the study did not separate them into clear diagnostic subgroups. With 40 patients with pain, the sample was small for testing multiple relationships among strength, kinematics, bony shape, and patient-reported outcomes. Reliability of the single-leg squat motion capture was tested only in asymptomatic participants, so it may not be as reliable in people with pain. The study did not measure muscle activation, joint forces, ankle movement, or trunk movement, which could influence hip kinematics. Standard deviations were large relative to group means, meaning movement patterns varied widely within both groups.

The authors report no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed.

Do not conclude that people with hip-related groin pain have abnormal hip adduction or internal rotation during single-leg tasks, or that correcting those angles will reduce pain. The study found no differences in those angles and no step-down kinematic differences, and it cannot show that weakness or squat depth caused the pain.