But What Are You Doing Now? Ecological Momentary Assessment of Sedentary Behavior Among Youth

Physical inactivity among youth is a major public health concern. To better understand youth inactivity, measures are needed that assess the many ways young people are inactive as well as the conditions under which these behaviors occur. Self-report techniques are the most cost-effective but have limitations when used with young people, largely because of their limited capacity for abstract reasoning and ability to perform detailed recall. PURPOSE The present study developed a self-report measure of sedentary behavior and physical activity among youth using principles of Ecological Momentary Assessment (EMA). An EMA approach circumvents many sources of bias known to plague self-report because participants are asked to make in-situ recordings of behavior at exact intervals only. Contemporaneous recordings were also made of the physical location and the social context of each behavior. METHODS A sample of 162 British youth (ages 12–15 yrs) completed an EMA diary across four days (three weekdays and one weekend day) between the months of February and June, 2001. RESULTS Intraclass correlations (ICC) between duration estimates of behavior derived from an EMA diary and a minute-by-minute diary were all high (mean ICC = 0.94). Stability estimates suggest that three days of assessment are required to estimate habitual patterns of sedentariness using the EMA approach. Analyses of temporal patterns revealed how highly prevalent sedentary behaviors were able to coexist with physical activity. CONCLUSIONS Preliminary data support the validity and reliability of an EMA diary. Data also suggest that television viewing should not be used as a marker of youth sedentariness because it appears unlikely to displace physical activity significantly. Further research should continue to develop valid and reliable measures of sedentary behavior and examine consistent correlates so that interventions can be developed to attenuate declining physical activity during the teenage years. Supported by grant \# 2000124 from the British Heart Foundation.