Relationships between knee valgus, hip-muscle strength, and hip-muscle recruitment during a single-limb step-down.

Context: Reduced strength and activation of hip muscles might correlate with increased weight-bearing knee valgus.

Objective: To describe relationships among frontal-plane hip and knee angles, hip-muscle strength, and electromyographic (EMG) recruitment in women during a step-down.

Design: Exploratory study.