ORIGINAL RESEARCH Frontal Plane Landing Mechanics in High-Arched Compared With Low-Arched Female Athletes Douglas W. Powell, PhD,* Nicholas J. Hanson, MS,† Benjamin Long, MS,‡ and D. S. Blaise Williams III, PhD§ Objective: To examine ground reaction forces (GRFs); frontal plane hip, knee, and ankle joint angles; and moments in high-arched (HA) and low-arched (LA) athletes during landing. Design: Experimental study. Setting: Controlled research laboratory. Participants: Twenty healthy female recreational athletes (10 HA and 10 LA). Interventions: Athletes performed 5 barefoot drop landings from a height of 30 cm. Main Outcome Measures: Frontal plane ankle, knee, and hip joint angles (in degrees) at initial contact, peak vertical GRF, and peak knee flexion; peak ankle, knee, and hip joint moments in the frontal plane. Results: Vertical GRF profiles were similar between HA and LA athletes (P = 0.78). The HA athletes exhibited significantly smaller peak ankle inversion angles than the LA athletes (P = 0.01) at initial contact. At peak vertical GRF, HA athletes had significantly greater peak knee (P = 0.01) and hip abduction angles than LA athletes (P = 0.02). There were no significant differences between HA and LA athletes in peak joint moments (hip: P = 0.68; knee: P = 0.71; ankle: P = 0.15). Conclusions: These findings demonstrate that foot type is asso- ciated with altered landing mechanics, which may underlie lower extremity injuries. The ankle-driven strategy previously reported in female athletes suggests that foot function may have a greater relationship with lower extremity injury than that in male athletes. Future research should address the interaction of foot type and gender during landing tasks. Key Words: foot, arch, injury, landing, kinetics, moments (Clin J Sport Med 2012;22:430–435) INTRODUCTION Landing is a common athletic maneuver encountered during many sports, including soccer, basketball, and volley- ball. High impact loading, sudden decelerations, and high vertical ground reaction forces (GRFs) associated with landing may have negative effects on the musculoskeletal system, including tendinopathies, joint pain, arthritis, and ligament injury. 1–3 Female athletes have a greater propensity for lower extremity injury than their male counterparts in landing and cutting sports, with the anterior cruciate ligament being the focus of many research studies. 4,5 Previous research has revealed kinematic and kinetic differences between male and female athletes during landing tasks. Specifically, female athletes have been shown to land with a more erect posture, exhibit greater knee flexion excursion, greater knee flexion velocities, greater knee valgus, and have a greater ankle con- tribution to energy dissipation during landing. 4,6–9 Addition- ally, rearfoot pronation has been associated with increased knee valgus during fatigued landing, suggesting a positive relationship between pronation and injury to the lower extremity. 8,10,11 Proximal to distal progression of shock attenuation during landing 12,13 suggests that malalignment or dysfunction of the foot results in altered loading patterns, which may result in lower extremity injury. Previous research has revealed a strong relationship between foot type and lower extremity injury. 14–20 Specifically, it has been shown that measures of foot function indicative of over-pronation are positively correlated with traumatic injury of the knee. 15,16,18,20 Due to the mitered hinge design of the ankle, increased rearfoot pronation results in greater tibial internal rotation and knee valgus, which has been previously associ- ated with traumatic lower extremity injury. 7,21 Low-arched (LA) feet have been shown to be flexible in nature 22 and have been associated with greater pronation than normal or high- arched (HA) feet. 23 This trend further suggests that foot type may be associated with common mechanisms of lower extremity injury during a landing task. In addition, previous research investigating gender differences in lower extremity injury has revealed that female athletes exhibit larger ankle motions in the frontal and sagittal planes than male athletes. 8,9 This ankle-driven strategy is theorized to be a compensatory strategy to reduce loading at the knee. However, the 2 studies Submitted for publication December 16, 2010; accepted March 28, 2012. From the *Neuromuscular Biomechanics Laboratory, Department of Exercise Science, Fairmont State University, Fairmont, West Virginia; †W. Michael Sherman Exercise Physiology Laboratory, Department of Health and Exer- cise Science, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio; ‡Human Performance and Biodynamics Lab- oratory, Department of Physical Therapy, Winston-Salem State University, Winston-Salem, North Carolina; and §Motion Analysis Laboratory, Depart- ment of Physical Therapy, East Carolina University, Greenville, North Carolina. The authors report no conflicts of interest. Corresponding Author: Douglas W. Powell, PhD, Neuromuscular Biome- chanics Laboratory, Department of Exercise Science, 1201 Locust Ave, Fairmont State University, Fairmont, WV 26554 (dwp0817@gmail.com). Copyright © 2012 by Lippincott Williams & Wilkins 430 | www.cjsportmed.com Clin J Sport Med  Volume 22, Number 5, September 2012