Effects of prophylactic lace-up ankle braces on kinetics and kinematics of the lower extremity during a state of fatigue.

Prophylactic lace-up braces are commonly used on athletes regardless of ankle injury history to reduce lateral ankle sprains (LAS). However, their ability to limit ankle sagittal range of motion has the potential to alter knee kinematics and is linked to chronic knee pathologies. Thirteen college-aged (6 males) and (7 females) experienced in landing/cutting sports completed a random crossover design study consisting of a 90° cutting task and a 15m beep test fatigue protocol. Braced conditions elicited a significant reduction in ankle sagittal displacement (ASD) in both pre-fatigue (-10.08°) and postfatigue (-9.51°). Also, w/brace increased in time to peak knee flexion pre-fatigue (3.26fps) and post-fatigue (1.74fps) and peak knee flexion pre-fatigue (6.14°) and post fatigue (10.92°). Prophylactic ankle braces limiting ASD appear to alter knee mechanics that are associated with chronic knee pathologies. Clinicians should use other prophylactic measures of hinge ankle braces or prevention programs to reduce LAS.