Yue Liao

Investigating children's physical activity and sedentary behavior using Ecological Momentary Assessment with mobile phones.

The risk of obesity during childhood can be significantly reduced through increased physical activity and decreased sedentary behavior. Recent technological advances have created opportunities for the real‐time measurement of these behaviors. Mobile phones are ubiquitous and easy to use, and thus have the capacity to collect data from large numbers of people. The present study tested the feasibility, acceptability, and validity of an electronic Ecological Momentary Assessment (EMA) protocol using electronic surveys administered on the display screen of mobile phones to assess childrens physical activity and sedentary behaviors. A total of 121 children (ages 9–13, 51% male, 38% at risk for overweight/overweight) participated in EMA monitoring from Friday afternoon to Monday evening during childrens nonschool time, with 3–7 surveys/day. Items assessed current activity (e.g., watching TV/movies, playing video games, active play/sports/exercising). Children simultaneously wore an Actigraph GT2M accelerometer. EMA survey responses were time‐matched to total step counts and minutes of moderate‐to‐vigorous physical activity (MVPA) occurring in the 30 min before each EMA survey prompt. No significant differences between answered and unanswered EMA surveys were found for total steps or MVPA. Step counts and the likelihood of 5+ min of MVPA were significantly higher during EMA‐reported physical activity (active play/sports/exercising) vs. sedentary behaviors (reading/computer/homework, watching TV/movies, playing video games, riding in a car) (P < 0.001). Findings generally support the acceptability and validity of a 4‐day EMA protocol using mobile phones to measure physical activity and sedentary behavior in children during leisure time.

The Acute Relationships Between Affect, Physical Feeling States, and Physical Activity in Daily Life: A Review of Current Evidence

Until recently, most studies investigating the acute relationships between affective and physical feeling states and physical activity were conducted in controlled laboratory settings, whose results might not translate well to everyday life. This review was among the first attempts to synthesize current evidence on the acute (e.g., within a few hours) relationships between affective and physical feeling states and physical activity from studies conducted in free-living, naturalistic settings in non-clinical populations. A systematic literature search yielded 14 eligible studies for review. Six studies tested the relationship between affective states and subsequent physical activity; findings from these studies suggest that positive affective states were positively associated with physical activity over the next few hours while negative affective states had no significant association. Twelve studies tested affective states after physical activity and yielded consistent evidence for physical activity predicting higher positive affect over the next few hours. Further, there was some evidence that physical activity was followed by a higher level of energetic feelings in the next few hours. The evidence for physical activity reducing negative affect in the next few hours was inconsistent and inconclusive. Future research in this area should consider recruiting more representative study participants, utilizing higher methodological standards for assessment (i.e., electronic devices combined with accelerometry), reporting patterns of missing data, and investigating pertinent moderators and mediators (e.g., social and physical context, intensity, psychological variables). Knowledge gained from this topic could offer valuable insights for promoting daily physical activity adoption and maintenance in non-clinical populations.

Momentary assessment of adults' physical activity and sedentary behavior: Feasibility and validity

Introduction: Mobile phones are ubiquitous and easy to use, and thus have the capacity to collect real-time data from large numbers of people. Research tested the feasibility and validity of an Ecological Momentary Assessment (EMA) self-report protocol using electronic surveys on mobile phones to assess adults’ physical activity and sedentary behaviors. Methods: Adults (N = 110; 73% female, 30% Hispanic, 62% overweight/obese) completed a 4-day signal-contingent EMA protocol (Saturday–Tuesday) with eight surveys randomly spaced throughout each day. EMA items assessed current activity (e.g., Watching TV/Movies, Reading/Computer, Physical Activity/Exercise). EMA responses were time-matched to minutes of moderate-to-vigorous physical activity (MVPA) and sedentary activity (SA) measured by accelerometer immediately before and after each EMA prompt. Results: Unanswered EMA prompts had greater MVPA (±15 min) than answered EMA prompts (p = 0.029) for under/normal weight participants, indicating that activity level might influence the likelihood of responding. The 15-min. intervals before versus after the EMA-reported physical activity (n = 296 occasions) did not differ in MVPA (p > 0.05), suggesting that prompting did not disrupt physical activity. SA decreased after EMA-reported sedentary behavior (n = 904 occasions; p < 0.05) for overweight and obese participants. As compared with other activities, EMA-reported physical activity and sedentary behavior had significantly greater MVPA and SA, respectively, in the ±15 min of the EMA prompt (ps < 0.001), providing evidence for criterion validity. Conclusion: Findings generally support the acceptability and validity of a 4-day signal-contingent EMA protocol using mobile phones to measure physical activity and sedentary behavior in adults. However, some MVPA may be missed among underweight and normal weight individuals.

Joint Physical Activity and Sedentary Behavior in Parent-Child Pairs

PURPOSE The research examined joint physical activity and sedentary behavior among 291 parent-child pairs who both wore an accelerometer and Global Positioning System (GPS) device during the same 7-d period. METHODS Children were 52.2% female, 8-14 yr, and 43.0% Hispanic. Parents were 87.6% female. An ActiGraph GT2M accelerometer and GlobalSat BT-335 GPS device collected activity and global positioning data, respectively. Linear distance between the parent and child for each 30-s epoch was calculated using geographic coordinates from the GPS. Joint behavior was defined as a separation distance less than 50 m between parents and children. RESULTS On average, during nonschool waking hours, parents and children spent 2.4 ± 4.1 min·d (mean ± SD) performing moderate-to-vigorous physical activity (MVPA) together and 92.9 ± 40.1 min·d in sedentary behavior together. Children engaged in an average of 10 min·d of MVPA during nonschool waking hours when their parent was nearby but not engaging in MVPA. During this same period, parents engaged in 4.6 min·d of MVPA when their child was nearby but not engaging in MVPA. Household income level and the childs age were negatively associated with joint MVPA. Girls engaged in a greater percentage of their total MVPA together with their parent than boys. Girls and older children engaged in more sedentary behavior together with their parent than boys and younger children. Older parents engaged in a greater percentage of their sedentary behavior together with their children than younger parents. CONCLUSIONS Replacing the time that parents and children spend together in sedentary pursuits with joint physical activity could have health benefits, especially for girls, older children, older parents, and higher income families.

Which type of sedentary behaviour intervention is more effective at reducing body mass index in children? A meta-analytic review

Sedentary behaviour is emerging as an independent risk factor for paediatric obesity. Some evidence suggests that limiting sedentary behaviour alone could be effective in reducing body mass index (BMI) in children. However, whether adding physical activity and diet‐focused components to sedentary behaviour reduction interventions could lead to an additive effect is unclear. This meta‐analysis aims to assess the overall effect size of sedentary behaviour interventions on BMI reduction and to compare whether interventions that have multiple components (sedentary behaviour, physical activity and diet) have a higher mean effect size than interventions with single (sedentary behaviour) component. Included studies (n = 25) were randomized controlled trials of children (<18 years) with intervention components aimed to reduce sedentary behaviour and measured BMI at pre‐ and post‐intervention. Effect size was calculated as the mean difference in BMI change between children in an intervention group and a control group. Results indicated that sedentary behaviour interventions had a significant effect on BMI reduction. The pooled effect sizes of multi‐component interventions (g = −0.060∼−0.089) did not differ from the single‐component interventions (g = −0.154), and neither of them had a significant effect size on its own. Future paediatric obesity interventions may consider focusing on developing strategies to decrease multiple screen‐related sedentary behaviours.

Investigating within-day and longitudinal effects of maternal stress on children's physical activity, dietary intake, and body composition: Protocol for the MATCH study

Parental stress is an understudied factor that may compromise parenting practices related to childrens dietary intake, physical activity, and obesity. However, studies examining these associations have been subject to methodological limitations, including cross-sectional designs, retrospective measures, a lack of stress biomarkers, and the tendency to overlook momentary etiologic processes occurring within each day. This paper describes the recruitment, data collection, and data analytic protocols for the MATCH (Mothers And Their Childrens Health) study, a longitudinal investigation using novel real-time data capture strategies to examine within-day associations of maternal stress with childrens physical activity and dietary intake, and how these effects contribute to childrens obesity risk. In the MATCH study, 200 mothers and their 8 to 12 year-old children are participating in 6 semi-annual assessment waves across 3 years. At each wave, measures for mother-child dyads include: (a) real-time Ecological Momentary Assessment (EMA) of self-reported daily psychosocial stressors (e.g., work at a job, family demands), feeling stressed, perceived stress, parenting practices, dietary intake, and physical activity with time and location stamps; (b) diurnal salivary cortisol patterns, accelerometer-monitored physical activity, and 24-hour dietary recalls; (c) retrospective questionnaires of sociodemographic, cultural, family, and neighborhood covariates; and (d) height, weight, and waist circumference. Putative within-day and longitudinal effects of maternal stress on childrens dietary intake, physical activity, and body composition will be tested through multilevel modeling and latent growth curve models, respectively. The results will inform interventions that help mothers reduce the negative effects of stress on weight-related parenting practices and childrens obesity risk.

Do stressed mothers have heavier children? A meta-analysis on the relationship between maternal stress and child body mass index

Child obesity continues to be a prevalent public health issue. This meta‐analysis synthesized 17 studies investigating the association between levels of psychological stress experienced by mothers and the body mass index of their children. The overall standardized mean difference effect size was positive and significantly different from zero in cross‐sectional d = 0.20 (k = 14, 95% confidence interval [CI]: 0.06, 0.34) and longitudinal studies d = 0.18 (k = 5, 95% CI: 0.00, 0.351) and had significant heterogeneity in both (cross‐sectional, Q[13] = 193.00, P < 0.001; longitudinal, Q[4] = 29.46, P < 0.001). In longitudinal studies, effect sizes were larger when children also would have experienced the stressor, Q(6) = 4.68, P < 0.05, for toddlers than infants, Q(4) = 5.04, P < 0.05, and in higher quality studies, Q(4) = 14.58, P < 0.05. Results highlight the potential benefits of including a parent stress management component in childhood obesity prevention programmes.

A Systematic Review of Methods and Procedures Used in Ecological Momentary Assessments of Diet and Physical Activity Research in Youth: An Adapted STROBE Checklist for Reporting EMA Studies (CREMAS).

Background Ecological momentary assessment (EMA) is a method of collecting real-time data based on careful timing, repeated measures, and observations that take place in a participant’s typical environment. Due to methodological advantages and rapid advancement in mobile technologies in recent years, more studies have adopted EMA in addressing topics of nutrition and physical activity in youth. Objective The aim of this systematic review is to describe EMA methodology that has been used in studies addressing nutrition and physical activity in youth and provide a comprehensive checklist for reporting EMA studies. Methods Thirteen studies were reviewed and analyzed for the following 5 areas of EMA methodology: (1) sampling and measures, (2) schedule, (3) technology and administration, (4) prompting strategy, and (5) response and compliance. Results Results of this review showed a wide variability in the design and reporting of EMA studies in nutrition and physical activity among youth. The majority of studies (69%) monitored their participants during one period of time, although the monitoring period ranged from 4 to 14 days, and EMA surveys ranged from 2 to 68 times per day. More than half (54%) of the studies employed some type of electronic technology. Most (85%) of the studies used interval-contingent prompting strategy. For studies that utilized electronic devices with interval-contingent prompting strategy, none reported the actual number of EMA prompts received by participants out of the intended number of prompts. About half (46%) of the studies failed to report information about EMA compliance rates. For those who reported, compliance rates ranged from 44-96%, with an average of 71%. Conclusions Findings from this review suggest that in order to identify best practices for EMA methodology in nutrition and physical activity research among youth, more standardized EMA reporting is needed. Missing the key information about EMA design features and participant compliance might lead to misinterpretation of results. Future nutrition and physical activity EMA studies need to be more rigorous and thorough in descriptions of methodology and results. A reporting checklist was developed with the goal of enhancing reliability, efficacy, and overall interpretation of the findings for future studies that use EMAs.

Momentary assessment of contextual influences on affective response during physical activity.

OBJECTIVE Higher positive and lower negative affective response during physical activity may reinforce motivation to engage in future activity. However, affective response during physical activity is typically examined under controlled laboratory conditions. This research used ecological momentary assessment (EMA) to examine social and physical contextual influences on momentary affective response during physical activity in naturalistic settings. METHOD Participants included 116 adults (mean age = 40.3 years, 73% female) who completed 8 randomly prompted EMA surveys per day for 4 days across 3 semiannual waves. EMA surveys measured current activity level, social context, and physical context. Participants also rated their current positive and negative affect. Multilevel models assessed whether momentary physical activity level moderated differences in affective response across contexts controlling for day of the week, time of day, and activity intensity (measured by accelerometer). RESULTS The Activity Level × Alone interaction was significant for predicting positive affect (β = -0.302, SE = 0.133, p = .024). Greater positive affect during physical activity was reported when with other people (vs. alone). The Activity Level × Outdoors interaction was significant for predicting negative affect (β = -0.206, SE = 0.097, p = .034). Lower negative affect during physical activity was reported outdoors (vs. indoors). CONCLUSIONS Being with other people may enhance positive affective response during physical activity, and being outdoors may dampen negative affective response during physical activity.

Understanding the physical and social contexts of children's nonschool sedentary behavior: an ecological momentary assessment study.

BACKGROUND Research on childrens sedentary behavior has relied on recall-based self-report or accelerometer methods, which do not assess the context of such behavior. PURPOSE This study used ecological momentary assessment (EMA) to determine where and with whom childrens sedentary behavior occurs during their nonschool time. METHODS Children (N = 120) ages 9-13 years (51% male, 33% Hispanic) wore mobile phones that prompted surveys (20 total) for 4 days. Surveys measured current activity (eg, exercise, watching TV), physical location (eg, home, outdoors), and social company (eg, family, friends). RESULTS Children engaged in a greater percentage of leisure-oriented (eg, watching TV) than productive (eg, reading, doing homework) sedentary behavior (70% vs 30%, respectively). Most of childrens sedentary activity occurred at home (85%). Childrens sedentary activity took place most often with family members (58%). Differences in physical context of sedentary behavior were found for older vs. younger children (P < .05). Type of sedentary behavior differed by gender, racial/ethnic group, and social context (P < .05). CONCLUSION Children may prefer or have greater opportunities to be sedentary in some contexts than others. Research demonstrates the potential for using EMA to capture real-time information about childrens sedentary behavior during their nonschool time.