Context: People with chronic ankle instability (CAI) exhibit less weight-bearing dorsiflexion range of motion (ROM) and less knee flexion during landing than people with stable ankles. Examining the relationship between dorsiflexion ROM and landing biomechanics may identify a modifiable factor associated with altered kinematics and kinetics during landing tasks.Objective: To examine the relationship between weightbearing dorsiflexion ROM and single-legged landing biomechanics in persons with CAI.Design: Cross-sectional study. Setting: Laboratory.Patients or Other Participants: Fifteen physically active persons with CAI (5 men, 10 women; age ¼ 21.9 6 2.1 years, height ¼ 168.7 6 9.0 cm, mass ¼ 69.4 6 13.3 kg) participated.Intervention(s): Participants performed dorsiflexion ROM and single-legged landings from a 40-cm height. Sagittal-plane kinematics of the lower extremity and ground reaction forces (GRFs) were captured during landing.Main Outcome Measure(s): Static dorsiflexion was measured using the weight-bearing-lunge test. Kinematics of the ankle, knee, and hip were observed at initial contact, maximum angle, and sagittal displacement. Sagittal displacements of the ankle, knee, and hip were summed to examine overall sagittal displacement. Kinetic variables were maximum posterior and vertical GRFs normalized to body weight. We used Pearson product moment correlations to evaluate the relationships between dorsiflexion ROM and landing biomechanics. Correlations (r) were interpreted as weak (0.00-0.40), moderate (0.41-0.69), or strong (0.70-1.00). The coefficient of determination (r 2 ) was used to determine the amount of explained variance among variables.Results: Static dorsiflexion ROM was moderately correlated with maximum dorsiflexion (r ¼ 0. Key Words: ankle sprain, drop landing, neuromuscular control, kinematics, kinetics Key PointsDuring a single-legged landing, persons with chronic ankle instability demonstrated moderate to strong relationships between dorsiflexion range of motion (ROM) and sagittal-plane kinematics at the knee and hip and vertical ground reaction forces. Persons with less dorsiflexion ROM exhibited a less flexed landing strategy that attenuated ground reaction forces less efficiently. Identifying dorsiflexion deficits may enable clinicians to implement interventions to increase ROM and potentially modify the landing biomechanics that persons with chronic ankle instability exhibit.

Clinical Scenario: Ankle injuries constitute a large number of injuries sustained by adolescent athletes participating in high school athletics. Prophylactic ankle bracing may be an effective and efficient method to reduce the incidence of ankle injuries in adolescent athletes in the secondary-school setting. Clinical Question: Do prophylactic ankle braces reduce the incidence of acute ankle injuries in adolescent athletes? Summary of Key Findings: Two of the three included studies reported that prophylactic ankle braces reduced the incidence of ankle injuries compared with no ankle bracing. Clinical Bottom Line: There is moderate evidence to support the use of prophylactic ankle braces in adolescent athletes, particularly those who participate in football and basketball, to reduce the incidence of acute ankle injuries. Strength of Recommendation: Grade B evidence exists that prophylactic ankle braces reduce the incidence of acute ankle injuries in adolescent athletes.