Cannon J, et al. - Given possible contributions of neuromuscular deficits at the trunk and hip to dynamic knee valgus and anterior cruciate ligament injury mechanisms have been suggested, researchers performed this cross-sectional analysis to determine the impact of lumbar spine joint rotational stiffness (JRS), and gluteal musculature contribution to hip JRS, on dynamic knee valgus. Greater gluteus medius frontal JRS and gluteus maximus transverse JRS was evident in relation to low valgus limbs vs high valgus limbs. Substantially decreased lumbar spine sagittal JRS was noted in cases with bilateral high valgus collapse vs the group with low valgus on both limbs. Beyond EMG analysis of limited muscles, lumbar spine and hip neuromuscular mechanisms that are possibly responsible for dynamic valgus in a drop vertical jump were specifically characterized for the first time in this analysis. Utilization of greater proximal JRS was seen in subjects who avoided high medial knee displacement.