Article

OBJECTIVE: To examine paired reflex depression changes post 20-minute bout each
of 2 training environments: stationary bicycle ergometer training (bicycle
training) and treadmill with body weight support and manual assistance (locomotor
training). DESIGN: Pretest-posttest repeated-measures. SETTING: Locomotor
laboratory. PARTICIPANTS: Motor incomplete SCI (n=12; mean, 44+/-16y); noninjured
subjects (n=11; mean, 30.8+/-8.3y). INTERVENTION: All subjects received each type
of training on 2 separate days. MAIN OUTCOME MEASURE: Paired reflex depression at
different interstimulus intervals (10 s, 1 s, 500 ms, 200 ms, and 100 ms) was
measured before and after both types of training. RESULTS: (1) Depression was
significantly less post-SCI compared with noninjured subjects at all
interstimulus intervals and (2) post-SCI at 100-millisecond interstimulus
interval: reflex depression significantly increased postbicycle training in all
SCI subjects and in the chronic and spastic subgroups (P<.05). CONCLUSIONS:
Phase-dependent regulation of reflex excitability, essential to normal
locomotion, coordinated by pre- and postsynaptic inhibitory processes (convergent
action of descending and segmental inputs onto spinal circuits) is impaired
post-SCI. Paired reflex depression provides a quantitative assay of inhibitory
processes contributing to phase-dependent changes in reflex excitability. Because
bicycle training normalized reflex depression, we propose that bicycling may have
a potential role in walking rehabilitation, and future studies should examine the
long-term effects on subclinical measures of reflex activity and its relationship
to functional outcomes.

Langue : ANGLAIS