Related Experiment Video
Updated: May 16, 2026

Visualization of Intensity Levels to Reduce the Gap Between Self-Reported and Directly Measured Physical Activity
Published on: March 7, 2019
Healthy for life: a randomized trial examining physical activity outcomes and psychosocial mediators
Beth A Lewis1, David M Williams, Brian C Martinson
1University of Minnesota, 1900 University Ave SE, Cooke Hall, Minneapolis, MN 55455, USA. blewis@umn.edu
Background:
Researchers theorize that interventions increase physical activity by influencing key theory-based mediators (e.g., behavioral processes). However, few studies have been adequately powered to examine the importance of mediators.
Purpose:
This study examined both physical activity behavior and psychosocial mediators in a randomized trial specifically powered to detect mediation.
Methods:
Healthy, sedentary adults (n = 448; 70 % Caucasian, 87 % women, mean age was 43) were randomly assigned to either a 6-month print-based theory tailored physical activity intervention (n = 224) or a 6-month health/wellness contact control arm (n = 224).
Results:
The print intervention arm exhibited greater increases in physical activity than the control arm at 6 and 12 months (p < .05). Additionally, behavioral processes were found to be an important mediator of physical activity behavior.
Conclusions:
It is important for researchers and practitioners to focus on increasing behavioral strategies for physical activity adoption. Future studies should examine other potential mediators of physical activity.
Related Concept Videos
Lifestyle Factors and Health
Benefits of Physical Activity
Physical activity, whether through structured exercise or casual activities like walking, biking, or dancing, is a cornerstone of a...
Stress Prevention and Stress Management Techniques VI
Motivation and Self-Determination
Motivation, the driving force behind behavior, plays a pivotal role at every stage of the change process. The research...
Models of Health Promotion and Illness Prevention II
The agent-host-environment model states that disease results from...
Models of Health Promotion and Illness Prevention I
The health belief model (HBM) attempts to predict health-related behavior in specific belief patterns. According to the HBM, a person's...
Levels of Health Promotion and Illness Prevention
In primary prevention, actions taken before disease onset prevent the disease from...
Cancer Prevention
Some...
