Dynamic knee valgus is associated with weakness in which muscle groups?

Dynamic knee valgus is associated with weakness in which muscle groups?

• A. Weak knee extensors
• B. Weak hip adductors
• C. Weak hip abductors and external rotators
• D. Weak gastrocnemius

Answer: (C)

Dynamic knee valgus happens when the thigh moves inward and the knee collapses toward the opposite side during weight-bearing tasks. The best explanation is weakness in the hip abductors and external rotators. When the hip abductors (gluteus medius and minimus) are weak, the pelvis can drop on the stance side, allowing the femur to adduct. If the external rotators are also weak, the femur tends to rotate internally, further pushing the knee into valgus. Together, these weaknesses reduce the thigh’s ability to stay aligned above the knee during activities like squats or landing, so the knee moves inward. Knee extensors mainly influence the ability to straighten the knee, not the sideways control of the knee, and the gastrocnemius is more involved with ankle and knee movement in the sagittal plane. Hip adductors would not typically cause the inward collapse the way weak abductors and external rotators do, since the abductors are the primary stabilizers in the coronal and transverse planes.

Dynamic knee valgus happens when the thigh moves inward and the knee collapses toward the opposite side during weight-bearing tasks. The best explanation is weakness in the hip abductors and external rotators. When the hip abductors (gluteus medius and minimus) are weak, the pelvis can drop on the stance side, allowing the femur to adduct. If the external rotators are also weak, the femur tends to rotate internally, further pushing the knee into valgus. Together, these weaknesses reduce the thigh’s ability to stay aligned above the knee during activities like squats or landing, so the knee moves inward.

Knee extensors mainly influence the ability to straighten the knee, not the sideways control of the knee, and the gastrocnemius is more involved with ankle and knee movement in the sagittal plane. Hip adductors would not typically cause the inward collapse the way weak abductors and external rotators do, since the abductors are the primary stabilizers in the coronal and transverse planes.