Accurate estimates of physical activity are essential for advancing research on the health benefits of physical activity; for understanding patterns and correlates that influence physical activity behavior; and for evaluating interventions designed to promote physical activity, improve health, or reduce obesity.

Considerable attention has been given to improving physical activity assessment methods, and research continues to further improve these methods. Many options are available for assessing physical activity, so it is important to appreciate and consider the relative advantages and disadvantages of the various measurement approaches. The goal of this User Guide is to provide an overview of the field of individual physical activity, offer general guidance about selecting measures to suit each user's needs, and make the Measures Registry a more user-friendly and valuable resource. Our most important recommendation is to think carefully about the aim of your study or evaluation project and to select a physical activity outcome measure that addresses this aim as directly as possible. This guidance should be applicable even as more measures are added to the Registry. We hope this User Guide encourages greater use of individual physical activity measures in research and practice.