The Effects of Ankle Braces on Lower Extremity Electromyography and Performance During Vertical Jumping: A Pilot Study

Ankle braces have been hypothesized to prevent ankle injuries by restricting range of motion (ROM) and improving proprioception at the ankle. As such, ankle braces are commonly worn by physically active individuals to prevent ankle injuries. Despite their widespread use, the effects that ankle braces have on athletic performance measures, such as vertical jumping, remains unclear. Furthermore, although ankle braces are known to restrict normal ROM at the ankle, little is known about the effects that ankle braces have on the lower extremity proximal to the ankle, specifically muscular activation. Therefore, the purpose of this pilot study was to determine if lower extremity surface electromyographic activity (sEMG) and performance was affected in 5 males and 5 females by wearing softshell (AE) and semi-rigid (T1) ankle braces during a Vertical Jump Test, and to establish a basis for future investigation. Vertical jump height was not significantly affected (p > .05) in the AE (37.49 ± 11.61 cm) and T1 (36.3 ± 11.77 cm) ankle brace conditions, relative to the no brace (38.17 ± 12.01 cm) condition. No significant differences in sEMG of the lateral gastrocnemius and biceps femoris were present across conditions. There was a tendency for sEMG of the rectus femoris to decrease when wearing AE (195.71 ± 100.43 %MVC) and T1 (183.308 ± 92.73 %MVC) braces, compared to no braces (210.08 ± 127.46 %MVC), and warrants further investigation using a larger sample. Until more research is conducted, however, clinicians should not be concerned about ankle braces significantly affecting proximal muscle activation during vertical jumping.