Date of Award

Spring 5-11-2012

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology and Health

First Advisor

L. Jerome Brandon

Second Advisor

Rebecca Ellis

Third Advisor

Jeffrey C. Rupp

Fourth Advisor

Lynda D. Woodruff

Abstract

The purpose of this study is to determine if African American Women (AAW) with low fitness levels have low fitness related to a lifestyle choice of decreased physical activity (PA) or the cardiovascular disadvantage of greater proportion of Type II (FT) muscle fibers.

Forty-eight apparently healthy AAW participated in the study. The women had no known risk factors for CVD; were sedentary (no structured fitness training program within last six months) or minimally fit (PA ≤ 3 x week for 20 minutes); and were not taking any prescription medications for blood pressure, diabetes, or lipid control. On the first visit the following measurements were taken: 1.) height and weight (electronic scale and stadiometer); 2.) body fat percentage (dual energy x-ray absorptiometry (DXA % body fat); and 3.) CRF (submaximal treadmill exercise test). On the second visit additional measurements included: 1.) blood pressure (stethoscope and sphygmomanometer); 2.) lipid profile and high sensitivity-C reactive protein (hs-CRP) (Cholestech LDX analyzer); 3.) thigh anthropometric measurements; 4.) isokinetic power and fatigue testing (KIN-COM dynamometer). Pearson product correlation coefficient (r) was used to analyze the relationship between the variables.

The results indicated that gross oxygen consumption at 85% maximal heart rate (VO2) was not significantly related to PA (r = -.06, p = .67) or FT fibers (r = 0.14, p = 0.34). VO2 was negatively correlated with hs-CRP (r = -.31, p < 0.05), systolic blood pressure (r = -0.47, p < 0.01), diastolic blood pressure (r = -0.42, p < 0.01), and DXA % body fat (r = -0.64, p < 0.01). There were no significant relationships between PA and any of the variables. FT fibers were negatively correlated with low density lipoprotein (r = -0.30, p < 0.05) and DXA % body fat (r = -0.46, p < 0.01).

In conclusion, low cardiorespiratory fitness in AAW does not seem to be a related to reported levels of PA or proportion of FT fibers. This suggests that there may be other factors that are contributing to the low levels of cardiorespiratory fitness observed in this sample of AAW.

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