Studies of a targeted risk reduction intervention through defined exercise(STRRIDE)

Purpose: The Studies of a Targeted Risk Reduction Intervention through Defi ned Exercise (STRRIDE) trial is a randomized controlled clinical trial desi gned to study the effects of exercise training regimens differing in dose ( kcal.wk(-1)) and/or intensity (relative to peak (V) over dotO(2)) on establ ished cardiovascular risk factors and to investigate the peripheral biologi c mechanisms through which chronic physical activity alters carbohydrate an d lipid metabolism to result in improvements in these parameters of cardiov ascular risk in humans. Methods: We will recruit 384 subjects and randomly assign them to one of three exercise training regimens or to a sedentary co ntrol group. The recruiting goal is to attain a subject population that is 50% female and 30% ethnic minority. The overall strategy is to use graded e xercise training regimens in moderately overweight subjects with impairment s in insulin action and mild to moderate lipid abnormalities to investigate whether there are dose or intensity effects and whether adaptations in ske letal muscle (fiber type, metabolic capacity, and/or capillary surface area ) account for improvements in insulin action and parameters of lipoprotein metabolism. We will study these variables before and after exercise trainin g, and over the course of a 2-wk detraining period. The study sample size i s chosen to power the study to examine differences in responses between sub jects of different gender and ethnicity to exercise training with respect t o the least sensitive parameter-skeletal muscle capillary density. Results: The driving hypothesis is that improvements in cardiovascular risk paramet ers derived from habitual exercise are primarily mediated through adaptatio ns occurring in skeletal muscle. Conclusion: Identification that amount and intensity of exercise matter for achieving general and specific health ben efits and a better understanding of the peripheral mechanisms mediating the responses in carbohydrate and lipid metabolism to chronic physical activit y will lead to better informed recommendations for those undertaking an exe rcise program to improve cardiovascular risk.