Degree

Doctor of Philosophy (PhD)

Department

Kinesiology

Document Type

Dissertation

Abstract

Exercise is a well-appreciated modulator of bone and has other positive implications for overall fitness and health. The purpose of this dissertation was to determine the effects of exercise on bone in conjunction with other known modifiers: old age, type II diabetes mellitus (T2DM), and ketogenic diets. The three studies discussed in this dissertation utilized multiple methods of measuring bone to examine the effect of exercise on bone in individuals with type II diabetes, rodents consuming a ketogenic diet, and older adults participating in a novel resistance training intervention. The first study examined the effects of a 9-month resistance, aerobic, or combination exercise intervention on bone in individuals with T2DM. Whole-body and whole-body derived regional measures of bone mineral density (BMD) were obtained via dual-energy x-ray absorptiometry (DXA) and used to determine the effects. While the entire cohort, control group included, showed significant increases in BMD after a 9-month intervention, the lack of differences between groups, was surprising. An effect of exercise on bone in individuals with T2DM was not revealed by measures of BMD. The second study utilized rodents to determine the effects of a 6-week ketogenic dietary intervention interceded by a 3-week exercise intervention on their trabecular and cortical bone morphology, measured via micro-computed tomography. Our results did not identify any detriments in bone morphology in response to a ketogenic diet alone, but positive changes in trabecular morphology and density induced by exercise in mice fed a control diet were negated by the ketogenic diet. The last study examined the effects of resistance training along with low intensity breaks in sedentary activity on BMD, trabecular bone score (TBS), and serum markers of bone turnover in older adults. Changes in whole-body BMD, lumbar spine BMD, and TBS were not found in response to the 4-month resistance training intervention. Serum markers for bone turnover did not provide any additional context due to reagent, equipment, and technician error. Future re-analysis may be attempted, but for the purpose of this dissertation, the analysis of blood markers for bone turnover was too poor and not included.

Date

3-26-2021

Committee Chair

Johannsen, Neil

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