Cardiovascular responses during submaximal electrical stimulation-induced leg cycling in individuals with paraplegia.
This study investigated the cardiovascular responses during electrical stimulation-induced leg cycling (ES-LCE) in people with paraplegia (PARA) compared with voluntary leg cycling (VOL) at similar levels of oxygen uptake in able-bodied (AB) individuals. Six PARA with sensory and motor complete spinal cord lesions (TS-T9) and six AB participated in this study. Oxygen uptake (VO2), stroke volume (SV), heart rate (HR) and cardiac output (Q) were measured at rest and during submaximal, steady-state leg cycling. At the highest power output achieved (9.2 +/- 2.4 W for PARA versus 42.8 +/- 1.0 W for AB), VO2 was augmented above resting levels to 0.75 +/- 0.11 min(-1) in PARA and to 0.74 +/- 0.071 min(-1) in AB. HR and SV were also increased during ES-LCE in PARA (92.1 +/- 8-6 beats min(-1) and 93.9 +/- 11.3 ml bea(-1), respectively) and during VOL in AB (83.9 +/- 9.2 beats min(-1) and 89.7 +/- 9.0 ml beat(-1), respectively). At an equivalent submaximal VO2, HR and SV were not different between the two groups, however, Q was higher in PARA (6.6 +/- 0.7 versus 4.1 +/- 0.9 1 min l(-1) deltaVO2). These data suggest that ES-LCE at relatively low power outputs elicits increases in several cardiovascular variables in PARA. Furthermore, it is possible that ES-LCE leads to a 'hyperkinetic circulation' (a greater Q for a given VO2).
Raymond
Jacqui
J
Rehabilitation Research Centre, The University of Sydney, NSW, Australia. J.Raymond@cchs.usyd.edu.au
Davis
Glen M
GM
van der Plas
Martinus
M
D000328:Adult; D004558:Electric Stimulation; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010264:Paraplegia / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology*