To date, there has not been a large-scale, randomized, controlled study examining the benefits of exercise training the diabetes risk factor, mainly insulin resistance, in African American males. National standardized estimates show that between 15% and 20% of all African Americans aged twenty and older have diabetes (including both diagnosed and undiagnosed). Regular physical activity is a modifiable risk factor for the development of diabetes. Although it has been shown that exercise training results in a reduction of diabetes in Caucasian adults, it cannot be assumed that the benefits derived in Caucasian adults apply to men of other ethnic groups. These types of studies are typically conducted at the university setting, which can be a barrier for African American participants compared to a community-based program. Therefore, we proposed to a randomized community-based trial assessing the effect of regular exercise on risk factors for diabetes in an exclusively African American male cohort. This proposal is entitled Aerobic Plus Resistance Training to Increase Insulin Sensitivity in African American Men (ARTIIS). The study group will consist of sedentary, healthy African American men aged 35 to 70 years. At this age group, we are recruiting men who are at the highest risk of developing diabetes and therefore, the group who is likely to benefit from an exercise program. Males in the exercise training group will engage in 150 minutes of aerobic activity, as well as 2 days of strength training. The target exercise intensity is 50-70% of VO2 max (aerobic) and 50-80% of 1RM (strength). This exercise dose is consistent with the current national physical activity recommendations, and therefore, ARTIIS will assist in determining if the current recommendations result in health benefits for African American males. We recognize that African American males are a difficult-to-reach population. In order to ensure successful participation we will utilize community-based fitness facilities to deliver the program. Thus males in the exercise training group will be able to exercise in their community. Primary outcome measures are risk factors for diabetes including insulin response to a glucose load, fasting insulin, and c-peptide. Secondary outcomes are cardiovascular fitness, muscular strength, body weight and composition, and psychological outcomes.
This study is designed to assess the effect of exercise training on insulin resistance in African American males. African American males have higher rates of diabetes and lower levels of fitness when compared to Caucasian males. A project such as this is necessary because there is evidence to show that exercise training can reduce the risk of developing diabetes, though no studies have been conducted in African American males. In addition, ARTIIS will test the effect adhering to the 2008 Physical Activity Guidelines for Americans (150 minutes of moderate intensity aerobic activity and 2 days of 20 minutes of muscular strength activity), on insulin resistance in African American men. This study will provide important information that can either strengthen or refine current physical activity recommendations. Furthermore, this intervention will be delivered through a community-based facility in order to increase the likelihood that the intervention will be sustainable.