The principal target groups within WIC for increasing physical activity are children 2 to 5 years of age, and pregnant and postpartum women. As indicated previously, physical activity assessment in WIC, like diet assessment, will have utility only at the group level. This is because even adult women, regardless of their educational level, can not accurately recall their own or their children’s physical activity. Such group assessments, however, are still important for education and monitoring, as described above, and research is required to overcome some of the challenges that exist in the valid, group-level assessment of physical activity in those served by WIC.
Several methods of assessing physical activity that are used in research (e.g., activity diaries or logs, direct observation of activity, motion sensors and heart rate monitoring [Baranowski et al., 1992; Goran, 1998; Kohl et al., 2000; Kriska and Caspersen, 1997; Pate, 1993; Sallis and Saelens, 2000; Welk et al., 2000]) could be used as “gold standard” references to conduct validity and reliability studies of practical instruments for WIC to assess physical activity at the group level using recalls. For example, such research might compare the results of a physical activity recall questionnaire (completed by the mother for her preschool child) against data from motion sensors that assess acceleration of the child’s body in three dimensions (Freedson and Miller, 2000).
Beyond the significant challenge of adequately describing physical activity levels in the WIC population, little is known about the factors influencing physical activity in the WIC population. It is widely perceived, for example, that concern about neighborhood safety is a major barrier to physical activity. However, the research base supporting this notion is small, and little is known about the factors that, if modified, could improve perceptions abut neighborhood safety, and thereby possibly increase physical activity levels. Whether preschool children or their mothers will be more active if they spend more time outdoors or less time watching television is not known.
However, the research to identify potential target indicators of physical activity must come after efforts to improve physical activity assessment, because target indicators cannot be identified without valid physical activity assessment tools. Furthermore, once behavioral targets are identified, interventions to modify these intermediate targets cannot be assessed without some measure of physical activity, which is the ultimate target of change.