Restoration of frequency-dependent depression of the H-reflex by passive exercise in spinal rats.
METHODS
Hyper-reflexia, measured as a decrease of low frequency-dependent depression of the H-reflex, is known to occur in both humans and animals after spinal cord injury (SCI). Previous studies have shown that passive exercise for 3 months could be used to restore low frequency-dependent depression of the H-reflex after SCI.


OBJECTIVE
To determine the effects of various periods of time on the ability of passive exercise to restore low frequency-dependent depression of the H-reflex.


METHODS
Spinal Cord Injury Mobilization Program of the Center for Translational Neuroscience, the research arm of the Jackson T Stephens Spine and Neuroscience Institute, Little Rock, AR, USA.


METHODS
Adult rats underwent complete spinal cord transection at the T10 level. The hindlimbs were passively exercised in different groups of rats for 1 h/day, 5 days/week for 15, 30, 45, 60, or 90 days, and low frequency-dependent depression of the H-reflex was tested.


RESULTS
Statistically significant low frequency-dependent depression of the H-reflex was evident by 30 days of exercise, although numerical reductions were seen even at 15 days. There was a linear decrease in low frequency-dependent depression of the H-reflex with duration of passive exercise.


CONCLUSIONS
Passive exercise can restore frequency-dependent depression of spinal reflexes in a time-dependent manner if used following complete spinal transection.
Reese
N B
NB
Department of Physical Therapy, University of Central Arkansas, Conway, AR 72205, USA.
Skinner
R D
RD
Mitchell
D
D
Yates
C
C
Barnes
C N
CN
Kiser
T S
TS
Garcia-Rill
E
E
D000818:Animals; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D012021:Reflex, Abnormal / Q000502:physiology; D013116:Spinal Cord / Q000601:surgery; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D013997:Time Factors