External power output changes during prolonged cycling with electrical stimulation.
This study analysed external power output and physiologic responses in 5 individuals with paraplegia during 40 minutes of electrical stimulation leg cycle exercise. Cycling was performed on a motor-driven isokinetic ergometer that enabled precise determinations of power output. Electrical stimulation was increased to 120-140 mA within the first 5 minutes and remained constant thereafter. Power output increased to 10.7 +/- 3.0 W after 2 minutes, dropped to 5.3 +/- 1.8 W after 6 minutes and subsequently recovered to 8.2 +/- 2.2 and 6.1 +/- 2.3 W after 19.5 and 40 minutes, respectively. Oxygen consumption increased to 0.47 +/- 0.09 l/min after 6 minutes and declined during the second half of the exercise bout. Gross mechanical efficiency after 19.5 minutes was elevated compared with the value after 6 minutes. Heart rate was significantly increased at the end of the trial. The time-dependent variability of power output and physiological responses question the concept of steady state for this form of exercise.
Theisen
D
D
Department of Physical Education and Rehabilitation, Faculty of Medicine, Catholic University of Louvain, Louvain-la-Neuve, Belgium. daniel.theisen@edph.ucl.ac.be
Fornusek
C
C
Raymond
J
J
Davis
G M
GM
D000328:Adult; D004558:Electric Stimulation; D016552:Ergometry / Q000295:instrumentation*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010264:Paraplegia / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*