title: Metabolic and hemodynamic responses to concurrent voluntary arm crank and electrical stimulation leg cycle exercise in quadriplegics.
abstract: This study determined the metabolic and hemodynamic responses in eight spinal cord injured (SCI) quadriplegics (C5-C8/T1) performing subpeak arm crank exercise (ACE) alone, subpeak functional electrical stimulation leg cycle exercise (FES-LCE) alone, and subpeak FES-LCE concurrent with subpeak ACE (hybrid exercise). Subjects completed 10 minutes of each exercise mode during which steady-state oxygen uptake (VO2), pulmonary ventilation (VE), heart rate (HR), cardiac output (CO), stroke volume (SV), mean arterial pressure (MAP), arteriovenous oxygen difference (a-v O2 diff), and total peripheral resistance (TPR) were determined. Although mean VO2 for both ACE alone and FES-LCE alone was matched at 0.66 l/mi, individualized power outputs ranged from 0-30 W (mean = 19.4 +/- 1.3) and 0-12.2 W (mean = 2.3 +/- 0.6), respectively. Hybrid exercise elicited significantly higher VO2 (by 54 percent), VE (by 39-53 percent), HR (by 19-33 percent), and CO (by 33-47 percent), and significantly lower TPR (by 21-34 percent) than ACE or FES-LCE performed alone (P less than or equal to 0.05). Stroke volume was similar between hybrid exercise and FES-LCE alone, and these two exercise modes evoked a significantly higher SV (by 41-56 percent) than during ACE alone. These data clearly demonstrate that hybrid exercise creates a higher aerobic metabolic demand and cardiac-volume load in SCI quadriplegics than either subpeak levels of ACE or FES-LCE performed separately. Therefore, hybrid exercise may provide more advantageous central cardiovascular training effects in quadriplegics than either ACE or FES-LCE alone.
authors.affiliation: Department of Veterans Affairs Medical Center, Dayton, OH 45428.
authors.forename: S P
authors.initials: SP
authors.lastname: Hooker
authors.forename: S F
authors.initials: SF
authors.lastname: Figoni
authors.forename: M M
authors.initials: MM
authors.lastname: Rodgers
authors.forename: R M
authors.initials: RM
authors.lastname: Glaser
authors.forename: T
authors.initials: T
authors.lastname: Mathews
authors.forename: A G
authors.initials: AG
authors.lastname: Suryaprasad
authors.forename: S C
authors.initials: SC
authors.lastname: Gupta
mesh_terms: D000328:Adult; D000332:Aerobiosis; D001132:Arm / Q000502:physiology; D004558:Electric Stimulation; D015444:Exercise / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D010100:Oxygen / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D011782:Quadriplegia / Q000378:metabolism / Q000503:physiopathology*
chemical_list: D010100:Oxygen