Relationship between the knee valgus moment and the hip abductor and adductor activity during single-leg landing

Objectives: To reveal the relationship between the knee valgus moment (KVM) and the hip abductor and adductor activity during single-leg landing.

Design: A cross-sectional study.

Setting: Laboratory-based, between April 2020 and May 2021.

Participants: Thirty female collegiate athletes.

Main outcome measures: KVM, hip adduction angle, hip internal rotation angle, knee valgus angle (KVA), gluteus medius muscle activity, adductor longus muscle activity, adductor longus to gluteus medius activity ratio (ADD/GMED), and vertical component of the ground reaction force (vGRF).

Results: Stepwise multiple regression analysis was performed. KVM was significantly positively associated with KVA (β = 0.613, p < 0.001), vGRF (β = 0.367, p = 0.010), and ADD/GMED (β = 0.289, p = 0.038).

Conclusions: Increased KVA, vGRF, and ADD/GMED were the independent factors that contributed to increased KVM during single-leg landing, and only ADD/GMED was found among the muscle activity values. The relative muscle activity of the gluteus medius and adductor longus, rather than those of the gluteus medius or adductor longus alone, may be useful in preventing anterior cruciate ligament injury during single-leg landing.