Effect of functional knee brace use on acceleration, agility, leg power and speed performance in healthy athletes.

Objectives: To investigate performance levels and accommodation period to functional knee brace (FKB) use in non-injured braced subjects while completing acceleration, agility, lower extremity power and speed tasks.

Design: A 2 (non-braced and braced conditions) × 5 (testing sessions) repeated-measures design.

Methods: 27 healthy male athletes were provided a custom fitted FKB. Each subject performed acceleration, agility, leg power and speed tests over 6 days; five non-braced testing sessions over 3 days followed by five braced testing sessions also over 3 days. Each subject performed two testing sessions (3.5 h per session) each day. Performance levels for each test were recorded during each non-braced and braced trial. Repeated measures analysis of variance, with a post hoc Tukey's test for any test found to be significant, were used to determine if accommodation to FKB was possible in healthy braced subjects.

Results: Initial performance levels were lower for braced than non-braced for all tests (acceleration p=0.106; agility p=0.520; leg power p=0.001 and speed p=0.001). However, after using the FKB for approximately 14.0 h, no significant performance differences were noted between the two testing conditions (acceleration non-braced, 0.53±0.04 s; braced, 0.53±0.04 s, p=0.163, agility non-braced, 9.80±0.74 s; braced, 9.80±0.85 s, p=0.151, lower extremity power non-braced, 58±7.4 cm; braced, 57±8.1 cm, p=0.163 and speed non-braced, 1.86±0.11 s; braced, 1.89±0.11 s, p=0.460).

Conclusions: An initial decrement in performance levels was recorded when a FKB is used during an alactic performance task. After 12.0-14.0 h of FKB use, performance measures were similar between the two testing conditions.