Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

A. J. Thomas; G. M. Davis; J. R. Sutton

doi:10.1055/s-0038-1636852

Methods of Information in Medicine, Table of Contents

Methods Inf Med 1997; 36(04/05): 372-375
DOI: 10.1055/s-0038-1636852

Original Article

Schattauer GmbH

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

A. J. Thomas

¹Rehabilitation Research Centre, The University of Sydney, Sydney, Australia

,

G. M. Davis

¹Rehabilitation Research Centre, The University of Sydney, Sydney, Australia

,

J. R. Sutton

¹Rehabilitation Research Centre, The University of Sydney, Sydney, Australia

› Author Affiliations

Abstract

Abstract:

Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

Keywords:

Exercise - Spinal Cord Injury - Cardiovascular Responses

Full Text

References

References
1 Adams L, Garlick J, Guz A, Murphy K, Semple SJG. Is the voluntary control of exercise in man necessary for the ventilatory response?. J Physiol 1984; 355: 71-83.
2 Adams L. et al. The role of spinal cord transmission in the ventilatory response to exercise in man. J Physiol 1984; 355: 85-97.
3 Scelsi R, Marchetti C, Poggi P, Lotta S, Lom-mi G. Muscle fiber type morphology and distribution in paraplegic patients with traumatic cord lesion. Acta Neuropathologica 1982; 57: 243-8.
4 Brice A. et al. Ventilatory and PaCO, responses to voluntary and electrically induced leg exercise. J Appl Physiol 1988; 64: 218-25.
5 Brice A. et al. Is the hyperpnoea of muscular contractions critically dependent on spinal afferents?. J Appl Physiol 1988; 64: 226-33.
6 Nakazono Y, Miyamoto Y. Cardiorespiratory dynamics in men in response to passive work. Japan J Physiol 1985; 35: 33-43.
7 Brown D. et al. Ventilatory response of spinal cord-lesioned subjects to electrically induced exercise. J Appl Physiol 1990; 68: 2312-21.
8 Figoni SF. et al. Acute haemodynamic responses of spinal cord injured individuals to functional neuromuscular stimulation-induced knee extension exercise. J Rehabil Res Develop 1991; 28: 9-18.
9 Glaser RM. et al. Central hemodynamic responses to lower limb FNS. Proc 9th Ann Internat Conf IEEE Eng Med Biol Soc 1987; 01: 615-7.
10 Davies CTM, Starkie DW. The pressor response to voluntary and electrically evoked isometric contractions in man. Eur J Appl Physiol 1985; 53: 359-63.
11 Waldrop TG, Rybicki KJ, Kaufman MP. Chemical activation of group I and II muscle afferents has no cardiorespiratory effects. J Appl Physiol: Respirat, Environ Exer Physiol 1984; 56: 1223-8.