Research: Exercise Epidemiology
Physical activity epidemiology is a topic area concerned with understanding the public health benefits of physical activity. It covers large-scale prospective studies involving the effect of levels of physical activity on health outcomes, predictors of physical activity level, physical activity measurement and assessment issues, and the conduct of clinical and community trials.
The program at the University of Maryland includes all these areas of research. Special emphasis is placed on community-based interventions. There are currently two NIH-funded community trials in process.
Trial of Activity for Adolescent Girls (TAAG)
The trial is being conducted at the University of Arizona (Tim Lohman, PI), University of Maryland (Deborah Rohm Young, PI), University of Minnesota (Leslie Lytle, PI), University of South Carolina (Russ Pate, PI), San Diego State University (John Elder, PI), and Tulane University (Larry Webber, PI). The Coordinating Center is at the University of North Carolina (June Stevens, PI). The National Heart, Lung, and Blood Institute are the program sponsors (Charlotte Pratt, project officer).
The TAAG intervention is grounded in the social-ecological model, which targets intrapersonal variables but emphasizes interpersonal, organizational, policy, and other environmental factors that influence human behavior. It emphasizes structured and unstructured (or unsupervised) physical activities in and out of school. The intervention consists of four major components: physical education; health education with activity challenges; partnerships among TAAG investigators, schools, and community agencies for physical activity, called Partnerships for Physical Activity; and promotional activities.
School levels of moderate-to-vigorous physical activity are the primary outcome variable measured in MET-weighted minutes of MVPA in cross-sectional samples of 6th and 8th grade girls taken from each school approximately 18 months apart. The Computer Science Applications (CSA) Actigraph monitors, worn by each girl in the sample for one week, supply a record of the magnitude of her movements throughout the week. The level of cardiorespiratory fitness is measured by means of a cycle ergometer in the 8th grade. Height, weight and skinfold measurements provide values for calculating body-mass index and percent body fat. Self-reported data are collected on secondary measures, mediators, descriptive variables, and environmental outcome variables. Other measures include classroom observations of physical activity.
Locally, the project is directed by Dr. Deborah Rohm Young. Dr. Young is a member of the TAAG Steering Committee, is chair of the Formative and Process Evaluation Subcommittee, and is a member of the Intervention Subcommittee, the Publications and Presentations Subcommittee, and the Health Education with Activity Challenges working group. Dr. Carolyn Voorhees, Department of Public and Community Health, is a member of the Design and Analysis Subcommittee and the Recruitment, Retention, and Tracking Subcommittee. She is also the PI of a TAAG ancillary study examining environmental characteristics associated with physical activity. Dr. Cheryl Alexander, Johns Hopkins Bloomberg School of Public Health, is the Partners for Physical Activity working group chair and a member of the Intervention Subcommittee. Dr. Joel Gittlesohn, Johns Hopkins Bloomberg School of Public Health, is chair of the Formative Assessment and Case Studies working groups. Dr. Margarita Treuth, Johns Hopkins Bloomberg School of Public Health, is a member of the Measurement Subcommittee. Dr. Brit Saksvig is the project coordinator and intervention director. She is also the chair of the Health Education with Activity Challenges working group, and a member of the Intervention Subcommittee, the Project Coordinators Subcommittee, and the Promotions working group. Ms. Mira Grieser is the process evaluation coordinator. She is a member of the Formative Assessment working group and the Measurement Logistics working group. Ms. Heidi Wilkes is the PE specialist, and is a member of the Physical Education working group. Ms. Berenice Rushovich and Ms. Jana Sharp, graduate research assistant, are the school-community liaisons and members of the Partners for Physical Activity working group. Ms. JoAnn Kuo is a graduate research assistant working with process evaluation and measurement tasks. Ms. Daheia Barr-Anderson, Ms. Jennie Wald, and Ms. Kantanahyee Whitt, graduate research assistants, are all working with the intervention-related activities. Ms. Sue Shang is the data manager for the trial, and Mr. Tavon English is the accounting clerk.
Project Heart
Project Heart - CAP is a randomized, controlled trial of a life skills-oriented, comprehensive physical activity program (CAP), combined with a family support component, versus standard PE class in adolescent girls attending public high school in Baltimore. The study evaluates the effects of a two-semester CAP intervention, conducted during PE class, on physical activity and cardiorespiratory fitness. Change in selected cardiovascular risk factors and psychological well-being are evaluated as secondary outcomes. The CAP intervention is conducted in 9th grade. The 1st semester focuses on basic behavioral skills training and participation in a variety of physical activity types. The second semester has a greater emphasis on problem solving and generalization components. The intervention designs were finalized with input from Youth and Parent Advisory Councils. Long-term follow-up of physical activity and other selected variables are assessed in order to determine maintenance of physical activity through spring semester 11th grade, for a total follow-up of 3 years.
Physical activity level, determined by the 7-day physical activity recall (PAR) and heart rate/activity monitoring, are the primary outcome variables for the trial. Other physical activity instruments are used to assess physical activity levels of study participants compared with national data and to test for contamination between groups by having an additional comparison group, female students at another magnet high school.
The intervention is designed to be congruent with the Social Action Theory, which emphasizes social interdependence, environmental factors, and problem-solving skills. The intervention places emphasis on providing sufficient information so students can make an informed decision about the personal benefits of a physically active lifestyle, develops problem-solving skills, and provides support from others. Ninth-grade students are randomized to either the CAP intervention (referred to as Alternative PE), conducted during PE class, or Standard PE (control condition). The intervention is designed to maximize the student's behavioral skills to continue a physically active lifestyle after the program is terminated. During the second semester of the intervention, the intervention focuses on personalizing the skills learned in the initial intervention (i.e., creating a personal exercise plan). Support from a family member, expected in most circumstances to be the mother, is built into the intervention to ensure that students receive optimal support for engaging in exercise.
