The impact of E-diaries and accelerometers on young adults' perceived and objectively assessed physical activity

ObjectiveE-diaries and accelerometers promise more objective, real-time measurements of health behavior. However, social-psychological theory suggests that using electronic behavioral monitoring may influence rather than just record physical activity (PA), especially when a device is novel.DesignParticipants (n = 146) were randomly assigned to either an accelerometer-only, e-diary-only, accelerometer + e-diary, or a no-technology control group for one week to assess how these technologies influenced PA, both perceived and actual, in young adults.MethodParticipants reported their PA, overall and number of discrete exercise sessions (DES) at baseline and follow-up; accelerometers provided daily step counts and e-diaries captured daily reports of PA for the active week of the study.ResultsAverage daily steps in the accelerometer-only and accelerometer + e-diary groups did not differ nor did daily reports of PA via e-diary compared to accelerometer + e-diary group, showing that neither technology affected actual PA. ANCOVAS tested group differences in perceived PA; The accelerometer-only group had increased perceived overall PA but not DES compared to no-technology control.ConclusionsAccelerometers may increase perceived overall PA, but the tested technologies did not increase DES or actual PA, suggesting that they may be viable unbiased measures of PA.     

Daily relations between social perceptions and physical activity among college women

ObjectivesThere is a need to develop more effective physical activity (PA) promotion programs for college women. Theory and evidence suggest that perceptions of the social environment play a role in college women’s PA, though little is known about how these perceptions are associated with PA at the day level. The goal of this study was to examine relations between changes in college women’s daily social perceptions and objectively assessed PA over seven days.DesignDaily diary method.MethodCollege women (n = 80, M_Age = 20, M_BMI = 23.1 kg/m²) wore Fitbit wristbands and completed daily self-reports of (1) the quantity and perceived intensity of their social interactions (positive/negative), and (2) the occurrence of social comparisons (based on appearance/health/status) for seven days.ResultsMultilevel models showed daily variability in predictors and outcomes (ps < 0.0001), as well as relations between within-person changes in social perceptions and PA. Increases in negative interactions (particularly those with friends) were consistently associated with decreases in daily PA, whereas increases in positive interactions showed limited relations (srs = −0.22-0.34). Days with health comparisons were days with greater PA for women who had stronger overall interest in comparisons, but were days with less PA for women with weaker overall interest (srs = 0.22–0.33). PA did not differ between days with vs. without appearance comparisons.ConclusionsSocial perceptions show meaningful day-to-day variability and relations with college women’s daily PA, and specific associations may be useful for improving tailored interventions for college women.