Differences in hip kinematics, muscle strength, and muscle activation between subjects with and without patellofemoral pain

PainSci » bibliography » Souza et al 2009
updated Dec 11, 2013

Tags: etiology, patellar pain, running, biomechanics, pro, arthritis, aging, pain problems, knee, leg, limbs, overuse injury, injury, exercise, self-treatment, treatment

PainSci notes on Souza 2009:

Is there any difference in women with patellofemoral pain in their hip kinematics, hip muscle strength and hip muscle activations patterns than women without pain? This is another small (40-subject) fishing expedition for biomechanical problems in people with knee pain (for another good example, see Ferber). They found some modest differences by some measures. As usual, there is no attempt to distinguish between cause and effect: it may well be that women with painful knees use their hip muscles differently because their knees hurt. The authors conclude that their “support the proposed link between abnormal hip function and PFP.” This is over-stated: their results are simply not inconsistent with that hypothesis. There’s a difference.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

STUDY DESIGN: Controlled laboratory study using a cross-sectional design.

OBJECTIVES: To determine whether females with patellofemoral pain (PFP) demonstrate differences in hip kinematics, hip muscle strength, and hip muscle activation patterns when compared to pain-free controls.

BACKGROUND: It has been proposed that abnormal hip kinematics may contribute to the development of PFP. However, research linking hip function to PFP remains limited.

METHODS AND MEASURES: Twenty-one females with PFP and 20 pain-free controls participated in this study. Hip kinematics and activity level of hip musculature were obtained during running, a drop jump, and a step-down maneuver. Isometric hip muscle torque production was quantified using a multimodal dynamometer. Group differences were assessed across tasks using mixed-design 2-way analyses of variance and independent t tests.

RESULTS: When averaged across all 3 activities, females with PFP demonstrated greater peak hip internal rotation compared to the control group (mean +/- SD, 7.6 degrees +/- 7.0 degrees versus 1.2 degrees +/- 3.8 degrees; P<.05). The individuals in the PFP group also exhibited diminished hip torque production compared to the control group (14% less hip abductor strength and 17% less hip extensor strength). Significantly greater gluteus maximus recruitment was observed for individuals in the PFP group during running and the step-down task.

CONCLUSION: The increased peak hip internal rotation motion observed for females in the PFP group was accompanied by decreased hip muscle strength. The increased activation of the gluteus maximus in individuals with PFP suggests that these subjects were attempting to recruit a weakened muscle, perhaps in an effort to stabilize the hip joint. Our results support the proposed link between abnormal hip function and PFP.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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