Files in this item
|(no description provided)|
|Title:||Circulorespiratory Responses of Spinal Cord Injured, Quadriplegic Men to Dynamic Physical Exercise|
|Author(s):||Figoni, Stephen Frank|
|Department / Program:||Physical Education|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||This study was designed to assess the circulorespiratory responses of spinal cord injured (SCI), quadriplegic men to dynamic upright physical exercise at selected relative and absolute workloads, and to compare these responses with an able-bodied reference group.
Subjects included 11 untrained, C5-7 complete SCI quadriplegic men and 11 untrained able-bodied men of similar age (27 yr), height (177 cm), and mass (65 kg). Exercise stress testing was performed with arm-crank ergometry, open-circuit spirometry, and impedance cardiography. Selected metabolic and hemodynamic variables were measured at three increasing relative workloads (0, 50, and 100% oxygen uptake (VO$\sb2$) reserve), and at two absolute workloads (VO$\sb2$ = 0.5 L/min, and cardiac output (CO) = 4.3 L/min).
Statistical analyses indicated that in the quadriplegic group power output (PO), VO$\sb2$, arteriovenous O$\sb2$ difference (a-vO$\sb2$), CO, and heart rate (HR) increased linearly with increasing relative workload, while stroke volume (SV), ejection fraction (EF), and end-diastolic volume (EDV) decreased linearly. During maximum exercise all variables were lower in the quadriplegic group than in the able-bodied group, except a-vO$\sb2$ and end-systolic volume (ESV), which were not different. SV, CO, and EDV were particularly low in the quadriplegic group. At VO$\sb2$ = 0.5 L/min, quadriplegics demonstrated lower SV, CO, EDV, and ESV, whereas PO, a-vO$\sb2$, and HR were higher among able-bodied subjects. At CO = 4.3 L/min, quadriplegics displayed lower SV, EDV, and ESV, but higher PO, VO$\sb2$, a-vO$\sb2$, HR, and the Heather myocardial contractile index, compared with able-bodied subjects.
SCI quadriplegic men may demonstrate subnormal needs and impaired abilities to circulate blood to metabolically active tissues during aerobic exercise. The differences in circulorespiratory responses between quadriplegic and able-bodied groups during dynamic upright physical exercise support the hypothesis of "hypokinetic circulation" that may characterize SCI quadriplegic men. Key features of this condition include (a) marked limitations on the maximum rates of aerobic metabolism and central circulation, (b) smaller increase in central circulation per unit increase in aerobic metabolism, (c) restricted positive cardiac chronotropy and inotropy, and (d) extremely limited cardiac preload.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-16|