Does wearing a functional knee brace affect hamstring reflex time in subjects with anterior cruciate ligament deficiency during muscle fatigue?
OBJECTIVE
To evaluate the effects of wearing a functional knee brace and muscle fatigue on hamstring reflex time in subjects with anterior cruciate ligament (ACL) deficiency.


METHODS
Repeated-measures clinical trial.


METHODS
Outpatient physical therapy department.


METHODS
Sixteen subjects with ACL deficiency.


METHODS
Subjects tested with and without a functional knee brace before and after an exercise protocol designed to fatigue the knee muscles.


METHODS
Latency of hamstring reflex muscle activity after sudden perturbation of the knee.


RESULTS
Wearing a knee brace shortened the hamstring reflex latency regardless of fatigue (F(1,15)=20.62, P<.001). Muscle fatigue lengthened the hamstring reflex time regardless of the bracing condition (F(1,15)=7.57, P<.015).


CONCLUSIONS
Wearing a functional knee brace facilitated hamstring muscle reflex, but muscle fatigue lengthened the hamstring reflex latency. Subjects with ACL deficiency should not rely on the knee brace to facilitate hamstring reflex for joint protection during prolonged sporting activities when muscles are fatigued.
Lam
Rita Y
RY
Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong.
Ng
Gabriel Y
GY
Chien
Eric P
EP
D000125:Achilles Tendon / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology*; D001915:Braces; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D018763:Muscle Fatigue; D011930:Reaction Time; D012026:Reflex, Stretch