The Effects of Gluteal Strength and Activation on the Relationship Between Femoral Alignment and Functional Valgus Collapse During a Single-Leg Landing.
Level 4 - case-series / case-control
Cross-sectional laboratory biomechanical study
PubMed 33662925 · doi:10.1123/jsr.2019-0528
What was done
Assessed 45 healthy females (mean age 20.1 years) and 45 healthy males (mean age 20.8 years) in a biomechanics research laboratory. Prone femoral alignment and isometric hip abduction and extension strength (via handheld dynamometry) were measured. Kinematics, kinetics, and surface electromyography (EMG) of the gluteus maximus and gluteus medius were collected during single-leg forward landings. Forward stepwise multiple linear regression models evaluated direct and mediating effects of gluteal strength and activation on functional valgus collapse metrics.
What was found
In females, lower hip abduction strength predicted greater peak hip adduction angle (R2 change = .10, P = .02), and higher hip-extensor activation predicted greater peak knee internal rotation angle (R2 change = .14, P = .01). In males, lower hip abduction strength predicted smaller peak knee abduction moments (R2 change = .11, P = .03), and the combination of lower hip abduction torque and lower gluteus medius activation predicted greater hip internal rotation angle (R2 change = .15, P = .04). No meaningful mediation effects were detected for gluteal strength or activation on the relationship between femoral alignment and functional valgus measures (upsilon_adj < .01).
Why it matters
These findings suggest that while gluteal strength and neuromuscular activation show weak-to-modest sex-specific associations with landing mechanics, they do not buffer or mediate the structural influence of anatomical femoral alignment on dynamic valgus collapse.
Limits
Cross-sectional laboratory design precludes establishing causal relationships between biomechanical markers and non-contact injury incidence. Isometric handheld dynamometry does not fully reflect dynamic, multi-planar muscle action during high-velocity landings. The cohort was limited to young, healthy participants, restricting generalizability to injured or elite athletic cohorts. Variance explained by the regression models was modest (10% to 15%).
Cited by
- supports The gluteus medius muscle functions to counteract medial inward pulling and internal rotation of the femur.