Insulin resistance is a precursor to type II diabetes mellitus and in conjunction with dyslipidaemia, hypertension, and obesity, these abnormalities constitute the metabolic syndrome. Insulin resistance usually develops before these other diseases and therefore identifying and successfully treating insulin resistant patients may have potentially great preventive value. Insulin resistance, obesity, and subsequently type II diabetes mellitus have increased dramatically and have reached epidemic proportions. The incidence of diabetes, and in particular type II diabetes mellitus, is increasing in developing countries and throughout the world and this is mainly as a result of increasingly sedentary lifestyle and obesity in an aging population. The specific aim of this study was to explore and describe the effect of a 14-week strength-based resistance training programme on insulin resistance amongst individuals aged 25 to 68 years, who are pre-diabetic, have T2DM, and/or are overweight. The research approach used in this investigation was explorative, experimental, and quantitative in nature. The quasi-experimental design consisted of a pre-test and post-test for an experimental and comparison group who were chosen through convenience and snowball sampling. A total of 30 participants were involved in this study, 15 participants in each group. The following dependent variables were selected, namely: body weight; BMI; body composition; waist-to-hip ratio; total cholesterol levels; triglyceride levels; HOMA-IR; and muscle strength for upper and lower body. Pre-and post-test analysis was performed at the Biokinetics and Sport Science Unit, located at the Nelson Mandela Metropolitan University (NMMU). Blood samples of the participants were drawn by nurses at the Health Clinic at the Nelson Mandela Metropolitan University and these blood plasma samples were stored at the Department of Microbiology and Biochemistry at NMMU for later analysis of glucose and insulin. The experimental group trained three times per week for a period of fourteen weeks, performing strength training exercises with progressive increments in the intensity of the exercise. The control group remained sedentary throughout the intervention period. Analysis of the data was conducted utilizing descriptive and inferential statistics. Analysis of variance (ANOVA) was used as a hypothesis-testing procedure to evaluate the mean differences. The following dependent variables showed a decrease in mean values: body weight, body mass index, body fat percentage, waist minimum, cholesterol and insulin. However these differences in results were not practically and statistically significant. The following dependent variables showed an increase in mean values: hip maximum, arm relaxed, arm flexed, thigh circumference, glucose and HOMA-IR. However these results were not practically and statistically significant. The mean differences in the plasma insulin level, pre- to post-test, between both groups indicated that a significant difference (t = -1.77, p = 0.044) existed between them. Cohen‟s d revealed a value of 0.64, which indicates moderate practical significance. The only dependent variable which showed both statistical and practical significance was sum of skinfolds. The findings for sum of skinfolds revealed that the mean differences, from pre- to post-test, between both groups indicated that a significant difference (t = -2.30, p = 0.015) existed between them. Cohen‟s d revealed a value of 0.84, which indicated a large practical significance. Although the sample size was too small to indicate generalisations to the diabetic population as a whole, strength training should be furthermore explored as an alternative and successful modality in the existing range of options available to the health and exercise professional to address the needs of the person with T2DM. The researcher proposed that a bigger sample size be used for the experimental and control group, the intervention period increased as well as various differences related to frequency, intensity and duration of strength training could possibly result in significant changes.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10104 |
| Date | January 2013 |
| Creators | Cairncross, Joy Claudia |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Health Sciences |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MA |
| Format | xvi, 181 leaves, pdf |
| Rights | Nelson Mandela Metropolitan University |
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