Validity of 24-h physical activity recall: physical activity measurement survey.

PURPOSE: The primary purpose of this study was to evaluate the validity of an interviewer-administered, 24-h physical activity recall (PAR) compared with that of the SenseWear Armband (SWA) for estimation of energy expenditure (EE) and moderate-to-vigorous physical activity (MVPA) in a representative sample of adults. A secondary goal was to compare measurement errors for various demographic subgroups (gender, age, and weight status). METHODS: A sample of 1347 adults (20-71 yr, 786 females) wore an SWA for a single day and then completed a PAR, recalling the previous day's physical activity. The participants each performed two trials on two randomly selected days across a 2-yr time span. The EE and MVPA values for each participant were averaged across the 2 d. Group-level and individual-level agreement were evaluated using 95% equivalence testing and mean absolute percent error, respectively. Results were further examined for subgroups by gender, age, and body mass index. RESULTS: The PAR yielded equivalent estimates of EE (compared with those in the SWA) for almost all demographic subgroups, but none of the comparisons for MVPA were equivalent. Smaller mean absolute percent error values were observed for EE (ranges from 10.3% to 15.0%) than those for MVPA (ranges from 68.6% to 269.5%) across all comparisons. The PAR yielded underestimates of MVPA for younger, less obese people but overestimates for older, more obese people. CONCLUSIONS: For EE measurement, the PAR demonstrated good agreement relative to the SWA. However, the use of PAR may result in biased estimates of MVPA both at the group and individual level in adults.

Validation of the SenseWear Pro Armband algorithms in children.

INTRODUCTION: The SenseWear Pro Armband (SWA) has been shown to be a valid and practical tool to assess energy expenditure (EE) in adults. However, recent studies have reported significant errors in EE estimates when the algorithms are applied to children. The purpose of this study was to assess the validity of recently developed algorithms developed to take into account children's unique movement patterns. METHODS: Twenty-one healthy children (14 boys and 7 girls), averaging 9.4 (1.3) yr of age, participated in a range of activities while being monitored with the SWA and a metabolic analyzer. The activity protocol lasted 41 min and included resting, coloring, playing computer games, walking on a treadmill (2, 2.5, and 3 mph), and stationary bicycling. RESULTS: The original algorithms overestimated EE by 32%, but average error with the newly developed algorithm was only 1.7%. There were no significant differences in overall estimates of EE across the 41-min trial (P > 0.05), but there was some variability in agreement for specific activities (average absolute difference in EE estimates was 13%). The average errors in EE estimates with the new algorithms were -20.7%, -4.0%, -4.9%, -0.9%, 0.6%, 3.5%, and -25.1% for resting, coloring, computer games, walking on a treadmill (2, 2.5, and 3 mph), and biking, respectively. Biking was the only activity with significant differences in EE estimations (P < 0.001). Average minute-by-minute correlations across individuals was r = 0.71 +/- 1.3 indicating that the relationships were consistent across individuals. CONCLUSIONS: The newly developed algorithms demonstrate improved accuracy for assessing EE for typical activities in children-including accurate estimation of light activities.

Validation of a computerized 24-hour physical activity recall (24PAR) instrument with pattern-recognition activity monitors.

PURPOSE: The purpose of this study was to examine the validity of a computerized 24-hour physical activity recall instrument (24PAR). METHODS: Participants (n=20) wore 2 pattern-recognition activity monitors (an IDEEA and a SenseWear Pro Armband) for a 24-hour period and then completed the 24PAR the following morning. Participants completed 2 trials, 1 while maintaining a prospective diary of their activities and 1 without a diary. The trials were counterbalanced and completed within a week from each other. Estimates of energy expenditure (EE) and minutes of moderate-to-vigorous physical activity (MVPA) were compared with the criterion measures using 3-way (method by gender by trial) mixed-model ANOVA analyses. RESULTS: For EE, pairwise correlations were high (r>.88), and there were no differences in estimates across methods. Estimates of MVPA were more variable, but correlations were still in the moderate to high range (r>.57). Average activity levels were significantly higher on the logging trial, but there was no significant difference in the accuracy of self-report on days with and without logging. CONCLUSIONS: The results of this study support the overall utility of the 24PAR for group-level estimates of daily EE and MVPA.

Rural-urban differences in physical activity, physical fitness, and overweight prevalence of children.

CONTEXT: The increasing prevalence of overweight in youth has been well chronicled, but less is known about the unique patterns and risks that may exist in rural and urban environments. A better understanding of possible rural-urban differences in physical activity profiles may facilitate the development of more targeted physical activity interventions. METHODS: Participants (1,687 boys; 1,729 girls) were recruited from fourth, fifth, and sixth grade classes in schools from urban areas, small cities, and rural areas. Multilevel modeling analysis was used to examine rural-urban differences in physical activity and prevalence of overweight. Physical activity was assessed by self-report and body mass index was calculated from measured height and weight. FINDINGS: Prevalence of overweight was higher among rural children (25%; P<.001) than children from urban areas (19%) and small cities (17%). Urban children were the least active overall (Cohens' d=-0.4), particularly around lunchtime while at school (d=-0.9 to -1.1). Children from small cities reported the highest levels of physical activity. CONCLUSIONS: The results of this study suggest there are rural-urban differences in children's prevalence of overweight and physical activity even within a fairly homogenous Midwestern state.