Title

Physiological limits and guidelines to prolonged arm exercise and thermal stress in persons with spinal cord injury

Date of Award

1997

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Interdepartmental Studies

First Committee Member

Shihab S. Asfour, Committee Chair

Second Committee Member

Mark S. Nash, Committee Member

Abstract

The primary objectives of this study were to: (1) test the hypothesis that physiological responses of individuals with spinal cord injury (SCI) do not differ from those of a non-disabled control group for the same temperature levels during submaximal exercise, (2) test the hypothesis that the physiological responses of individuals with SCI do not change with increasing temperature levels, and (3) test the validity of the Borg's RPE (Ratings of Perceived Exertion) Scale for individuals with SCI.To achieve the objectives of this research, an experiment was conducted to examine physiological responses of persons with paraplegia and a control group during arm cranking exercise at 50% of their individual peak oxygen uptake (VO$\sb2).$ Each subject underwent three experimental treatments. The duration of exercise treatment was 30 minutes, while each treatment was conducted at different temperature levels, namely, $80\sp\circ$F, 90$\sp\circ$F, and 100$\sp\circ$F. The humidity level was kept at 50% for all exercise treatments.Eight male subjects with SCI between T1-T12 (DB), and eight healthy male subjects (ND) volunteered to participate in this study. A mixed design, with two within-subject factors, and one between-subjects factor was utilized in this experiment. The results of the experiment were analyzed using multivariate analysis of variance (MANOVA) followed by analysis of variance (ANOVA) as needed.The results of the experiment indicated that heart rates (HR) for the DB were not significantly different from the HR for the ND, however temperature levels and time intervals significantly affected HR for both groups. Heart rate demonstrated a progressive increase throughout the duration of the exercises for both subject groups. This upward drift could be attributed to a decrease in stroke volume (SV) as a result of increasing peripheral demands to dissipate heat. The VO$\sb2$ was significantly different for the two study groups. Temperature levels and the time intervals did not have any significant effect on the VO$\sb2.$ Minute ventilation was not affected by any of the dependent variables. It was also concluded that use of ratings of perceived exertion was not a valid measure of subjective effort for the DB subjects.

Keywords

Biology, Animal Physiology; Health Sciences, Recreation

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9805908