This thesis describes studies related to human body composition,
concentrating upon methodology of measurement, and a study on the influence of
brisk walking programme upon healthy, previously sedentary middle-aged men.
In chapter I, the principles of the techniques used for measurement of body
composition in this thesis are discussed. The limitations and potential sources of error
associated with each are discussed. The response of body composition to exercise,
and the relationship of this response to changes in cardiovascular risk factors are
considered. General methods are described in chapter 2.
Techniques suitable for measurement of body composition in "field"
conditions are evaluated in chapters 3 and 4. Near infra-red interactance was found to
under-estimate fatness, to an increasing extent with increasing fatness. Bio-electrical
impedance estimates of body composition from different sets of prediction equations
from the literature differed significantly. Most overestimated fatness, to an increasing
extent with increasing fatness.
In chapter 5 techniques for measurement of subcutaneous adipose tissue are
evaluated by comparison with A-mode ultrasound. Skinfold thicknesses were better
correlated with subcutaneous adipose tissue thickness than were interactance data.
Chapters 6 and 7 describe a year-long study on the effects of a brisk walking
programme on healthy, previously sedentary middle-aged men. Volunteers were
randomly allocated to walking or control groups (n = 42 and 23 respectively). Brisk
walking for on average 27 minutes per day was not found to influence body
composition, although significant changes in lower limb skinfold thicknesses were
observed. The relationship of changes in blood pressure and blood concentrations of
total cholesterol, lipoprotein-cholesterol subfractions and triglycerides with changes
in body composition and fat distribution is examined.
Energy intake did not change during the study, despite the expected increase
in energy expenditure, and lack of change in body composition. Changes in dietary
cholesterol and fatty acid intakes during the year are described, and related to changes
in cardiovascular risk factors.
In conclusion, newer field techniques were not found to be a better predictor
of body composition than skinfold thicknesses. Participation in the walking
programme did not significantly influence body composition or energy intake.
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/
Publication date
1992
Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.