Long latency reflex response of superficial trunk musculature in athletes with chronic low back pain.
OBJECTIVE
Incidence of Low Back Pain (LBP) in athletes is as high as 30%. Patients with LBP show altered postural and neuromuscular responses to various functional tasks. The objective of the study was to compare long latency reflex response (occurring between 40 to ∼ 100 ms duration) in athletes with chronic LBP with asymptomatic athletes.


METHODS
Surface electromyography (EMG) of superficial trunk muscles - Rectus Abdominis (RA) and Erector Spinae (ES) were studied in athletes with chronic LBP (n=24) and asymptomatic athletes (n=25). Perturbations were introduced in standing both expectedly and unexpectedly. The latency of onset and the Root Mean Square (RMS) amplitudes within the reaction duration were compared between the two groups.


RESULTS
The latency of onset was delayed in Unexpected perturbations but no change was observed in Expected tasks. The mean RMS amplitudes were significantly lower in both tasks for RA and in the Expected task for ES (p< 0.05).


CONCLUSIONS
Chronic LBP athletes exhibit a delay in onset latency to Unexpected perturbations and reduced long latency response amplitudes to perturbation tasks compared to asymptomatic athletes. These changes could predispose athletes to recurrent low back pain and further injury.
Faculty of Sports Medicine and Physiotherapy, Guru Nanak Dev University, Amritsar, Punjab, India.
S
S
Shenoy
H
H
Balachander
J S
JS
Sandhu
D000328:Adult; D056352:Athletes; D059350:Chronic Pain / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology; D011187:Posture / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012018:Reflex / Q000502:physiology*
EMG; Long latency reflex; athletes; low back pain; perturbation