Performance effects of functional knee brace removal and prolonged use in healthy male athlete: Lower extremity power, acceleration, speed, and agility

Abstract

Objectives: Knee braces were introduced to sports 30 years ago. However, knee brace use for non-contact anterior cruciate ligament injury prevention intervention remains contentious due to concerns about performance hindrances. Since knee brace use is a potential modifiable risk factor, we aimed to investigate the effect of discounting and continued functional knee brace (FKB) on lower extremity power-vertical jump (VJ), acceleration, speed, and agility performance.

Design: Prospective cohort crossover study.

Methods: Twenty-seven healthy male athletes performed seven tests, over six days of 12 test sessions (S), during three test conditions (non-braced, braced, and removed brace or continued brace use). This study focuses on VJ, acceleration, speed, and agility performance during S12 when athletes were randomly selected to remove the FKB after 17.5 h or continue using the FKB for 21.0 h.

Results: After brace removal, nonsignificant performance levels improved in the VJ (2.7 %; 95 % CI 52.5-62.8; Cohen's effect size (ES) = trivial), acceleration (1.8 %; 95 % CI 0.500-0.562; ES = small), and agility (0.5 %; 95 % CI 9.25-10.13; ES = trivial), while a nonsignificant slower speed was recorded (0.5 %; 95 % CI 1.81-1.95; ES = trivial). Continued brace use led to a nonsignificant performance improvement in all tests; VJ (3.1 %; 95 % CI 53.5-60.2; ES = small), acceleration (1.5 %; 95 % CI 0.511-0.561; ES = trivial), speed (1.0 %; 95 % CI 1.83-1.95; ES = trivial), and agility (1.8 %; 95 % CI 9.26-10.04; ES = trivial).

Conclusions: Removal of FKB led to improved performance in three performance tests, while continued brace use improved performance in all four tests.

Keywords: Acceleration; Agility; Anterior cruciate ligament; Knee brace; Power-vertical jump; Speed.