The association of ankle dorsiflexion range of motion with hip and knee kinematics during the lateral step-down test

STUDY DESIGN: Controlled laboratory study. BACKGROUND: Altered hip and knee kinematics have been associated with several knee disorders, including anterior cruciate ligament tear, patellofemoral pain, and iliotibial band syndrome. Limited ankle dorsiflexion (DF) range of motion (ROM), which has been linked with some of these disorders, has also been associated with altered knee kinematics. OBJECTIVE: To explore the association of ankle DF ROM with hip and knee kinematics during a step-down task. METHODS: Thirty healthy participants underwent a 3-D analysis of hip and knee kinematics during a lateral step-down test, followed by measurement of ankle DF ROM in weight bearing (WB) and non-weight bearing (NWB). Participants were dichotomized using the median values into lowand high-DF subgroups within both WB and NWB. Hip and knee kinematics were compared between the low-and high-DF subgroups. RESULTS: Participants in the low-DF subgroups exhibited greater peak hip adduction (WB, P = .02; NWB, P<.01) and greater peak knee external rotation (WB, P = .02; NWB, P<.01) compared with participants in the high-DF subgroups. In addition, participants in the low-DF WB subgroup exhibited decreased peak knee flexion compared with participants in the high-DF WB subgroup (P<.01). CONCLUSION: Individuals with lower ankle DF ROM exhibited hip and knee kinematics previously associated with several knee disorders, suggesting that this impairment may be involved in the pathogenesis of the same disorders. Assessment of ankle DF ROM may be useful as part of a preparticipation screening. Furthermore, deficits in ankle DF ROM may need to be addressed in individuals with altered movement patterns. J Orthop Sports Phys Ther 2016;46(11):1002-1009.