6-MONTH PHYSICAL-ACTIVITY AND FITNESS CHANGES IN PROJECT ACTIVE, A RANDOMIZED TRIAL

Purpose: Project Active is a randomized clinical trial (N = 235) compa ring a lifestyle physical activity program with a structured exercise program in changing physical activity (total energy expenditure [kcal kg(-1) d(-1)]) and cardiorespintory fitness ((V) over dot O-2peak in m L kg-l min-l). Methods: Sedentary but healthy adults (N = 235) aged 35 -60 years received 6 months of intensive intervention. Results: Analys is of covariance (ANCOVA), adjusting for baseline measure, age, gender , body mass index (BMI), cohort, and ethnicity, showed that at 6 month s both lifestyle and structured soups significantly increased energy e xpenditure over baseline (P < 0.001). The mean increases +/- SE, 1.53 +/- 0.19 kcal kg(-1) d(-1) for the lifestyle group and 1.34 rt: 0.?0 k cal kg-l d-l for the structured group, were not significantly differen t between groups (P = 0.49). For cardiorespiratory fitness, both group s had significant increases from baseline (P < 0.001). Mean increases +/- SE were 1.58 +/- 0.33 mL kg-l min-l and 3.61 +/- 0.33 ml kg-l min( -1) for the lifestyle and structured groups, respectively. This was si gnificantly greater in the structured group (P < 0.081). We also studi ed changes in intensity of physical activity. Both groups significantl y increased moderate intensity activity from baseline, but the increas e was significantly greater in the lifestyle group than the structured group (P = 0.02). In contrast, the structured group increased its har d activity more than the lifestyle group, but the difference was not s ignificantly different (P = 0.18). Very hard activity significantly in creased (P < 0.01) for both groups by 0.25 kcal kg(-1) d(-1). Conclusi on: Both intervention approaches are effective for increasing physical activity and fitness over a 6-month period in initially sedentary men and women.