International Comparison of the Levels and Potential Correlates of Objectively Measured Sedentary Time and Physical Activity among Three-to-Four-Year-Old Children.

Physical activity (PA) patterns track from childhood through to adulthood. The study aimed to determine the levels and correlates of sedentary time (ST), total PA (TPA), and moderate-to-vigorous PA (MVPA) in preschool-aged children. We conducted cross-sectional analyses of 1052 children aged three-to-four-years-old from six studies included in the International Children's Accelerometry Database. Multilevel linear regression models adjusting for age, gender, season, minutes of wear time, and study clustering effects were used to estimate associations between age, gender, country, season, ethnicity, parental education, day of the week, time of sunrise, time of sunset, and hours of daylight and the daily minutes spent in ST, TPA, and MVPA. Across the UK, Switzerland, Belgium, and the USA, children in our analysis sample spent 490 min in ST per day and 30.0% and 21.2% of children did not engage in recommended daily TPA (≥180 min) and MVPA (≥60 min) guidelines. There was evidence for an association between all 10 potential correlates analyzed and at least one of the outcome variables; average daily minutes spent in ST, TPA and/or MVPA. These correlates can inform the design of public health interventions internationally to decrease ST and increase PA in preschoolers.

Parental characteristic patterns associated with maintaining healthy physical activity behavior during childhood and adolescence.

BACKGROUND: Parental characteristics that influence child physical activity (PA) behavior often co-occur. An analytic approach that considers these co-occurring patterns can help researchers better understand the overall context of parental influence. The study aims were to: (1) identify diverse patterns of the relationships among parental characteristics, (2) examine the influence of these parental patterns on child sport participation and moderate-to vigorous-intensity PA (MVPA) trajectories during childhood and adolescence, and (3) examine whether family support mediates the influence of the parental patterns on child sport participation and MVPA trajectories. METHODS: We used data from 408 Iowa Bone Development Study cohort families (97% Caucasians; 65 % mothers with a 4-year college degree). From ages 5 to 19 years, the cohort participated in seven accelerometry assessments, reported sports participation every 6 months, and reported perceived family support for PA at age 15. Parents reported family income, education level, and regular PA participation in high school and adulthood. Structural equation modeling was conducted to identify the latent classes represented among these parental characteristics. Sex-adjusted multivariable logistic regression analyses were conducted to predict sports participation trajectories and MVPA trajectories by latent class and family support. RESULTS: Three parent latent classes were identified: higher family socioeconomic status (SES) and regular PA in both high school and adulthood by both the father and mother (Group 1); lower family SES and regular PA in high school by the father (Group 2); and lower family SES and no regular PA in high school by the father (Group 3). Sex-adjusted ORs of the "drop-out from sports participation" pattern for the children in Groups 1 and 2, compared to Group 3, were 0.38 (95% CI = 0.20, 0.72) and 0.51 (95% CI = 0.26, 1.00), respectively. Sex-adjusted ORs of the "decreasing from moderate MVPA" pattern for the children in Groups 1 and 2, compared to Group 3, were 0.29 (95% CI = 0.11, 0.75) and 1.16 (95% CI = 0.40, 3.37), respectively. Adding family support to the logistic regression model only slightly changed the ORs. CONCLUSIONS: The findings from this study suggest that among lower SES families, the father's role may be important to promote youth to sustain sports participation.

Association between maternal education and objectively measured physical activity and sedentary time in adolescents.

BACKGROUND: Investigating socioeconomic variation in physical activity (PA) and sedentary time is important as it may represent a pathway by which socioeconomic position (SEP) leads to ill health. Findings on the association between children's SEP and objectively assessed PA and/or sedentary time are mixed, and few studies have included international samples. OBJECTIVE: Examine the associations between maternal education and adolescent's objectively assessed PA and sedentary time. METHODS: This is an observational study of 12 770 adolescents (10-18 years) pooled from 10 studies from Europe, Australia, Brazil and the USA. Original PA data were collected between 1997 and 2009. The associations between maternal education and accelerometer variables were examined using robust multivariable regression, adjusted for a priori confounders (ie, body mass index, monitor wear time, season, age and sex) and regression coefficients combined across studies using random effects meta-analyses. Analyses were conducted in March 2014. RESULTS: Adolescents of university educated mothers spent more time sedentary (9.5 min/day, p=0.005) and less time in light activity (10 min/day, p<0.001) compared with adolescents of high school educated mothers. Pooled analysis across two studies from Brazil and Portugal (analysed separately because of the different coding of maternal education) showed that children of higher educated mothers (tertiary vs primary/secondary) spent less time in moderate to vigorous PA (MVPA) (6.6 min/day, p=0.001) and in light PA (39.2 min/day: p<0.001), and more time sedentary (45.9 min/day, p<0.001). CONCLUSIONS: Across a number of international samples, adolescents of mothers with lower education may not be at a disadvantage in terms of overall objectively measured PA.

The effect of family and friend support on physical activity through adolescence: a longitudinal study.

BACKGROUND: This study examined if family and friend support predicted adolescent physical activity (PA) across a five-year time span. METHODS: The Iowa Bone Development Study collected objective measures of physical activity and self-report of physical activity psychosocial factors at ages 13 (n = 306), 15 (n = 356), and 17 yr (n = 317). Total moderate and vigorous-intensity PA (MVPA) and MVPA after 3 pm on weekdays (MVPA-PM Weekday) were measured using ActiGraph accelerometers. Family Support for PA and Friend Support for PA scales were measured using the Choices questionnaire. Models were adjusted for SES (mother's education) and somatic maturity (Mirwald predictive equations for maturity offset). Spearman correlation coefficients examined tracking of scales at ages 13, 15 and 17. Logistic regression estimated the odds ratio for being in the lowest tertile of each scale at age 17 if in the lowest tertile at age 13. Linear mixed regression models investigated associations between these scales and MVPA outcomes over time. RESULTS: Two- and five-year intra-variable tracking associations for Family Support and Friend Support scales were moderate (r = 0.32-0.58), except for the comparison between age 13 and age 17 Friend Support for girls, which resulted in a low association (r = 0.26). Boys and girls in the lowest tertile for support at age 13 were more likely to remain in the lowest tertile at age 17 compared to those in the middle and upper tertiles. The regression models indicated that when all other factors were held constant, an increase in family and/or friend support resulted in an increase in both MVPA outcomes CONCLUSIONS: From early to late adolescence, support for PA from the family and/or support from friends results in higher levels of total and discretionary MVPA. However, the importance of support in predicting MVPA decreased with age.

Tracking of accelerometry-measured physical activity during childhood: ICAD pooled analysis.

BACKGROUND: Understanding of physical activity (PA) tracking during childhood is important to predict PA behaviors and design appropriate interventions. We compared tracking of PA according to PA level and type of day (weekday/weekend) in a pool of five children's cohort studies. METHODS: Data from ALSPAC, CLAN, Iowa Bone Development Study, HEAPS, PEACH were extracted from the International Children's Accelerometry Database (ICAD), resulting in 5,016 participants with age, gender, and accelerometry data at both baseline and follow-up (mean age: 10.3 years at baseline, 12.5 years at follow-up). Daily minutes spent in moderate- and vigorous-intensity PA (MVPA) and vigorous-intensity PA (VPA) was categorized into quintiles. Multinomial logistic regression models were fit to predict follow-up (M)VPA from baseline (M)VPA (reference: 20- < 80%tile), age at follow-up, and follow-up duration. RESULTS: For the weekday, VPA tracking for boys with high baseline VPA was higher than boys with low baseline VPA (ORs: 3.9 [95% CI: 3.1, 5.0] vs. 2.1 [95% CI: 1.6, 2.6]). Among girls, high VPA was less stable when compared low VPA (ORs: 1.8 [95% CI: 1.4, 2.2] vs. 2.6 [95% CI: 2.1, 3.2]). The pattern was similar for MVPA among girls (ORs: 1.6 [95% CI: 1.2, 2.0] vs. 2.8 [95% CI: 2.3, 3.6]). Overall, tracking was lower for the weekend. CONCLUSIONS: PA tracking was higher on the weekday than the weekend, and among inactive girls than active girls. The PA "routine" of weekdays should be used to help children establish healthy PA patterns. Supports for PA increase and maintenance of girls are needed.

Paths to leisure physical activity among adults with intellectual disabilities: self-efficacy and social support.

PURPOSE: This study tested a path model that included perceptions of social support and self-efficacy for leisure physical activity and leisure physical activity participation among adults with intellectual disabilities. DESIGN: A cross-sectional design was used. Data was collected via oral interview. SETTING: Community-based group, supported-living settings in one Midwestern state. SAMPLE: A total of 152 adults with mild to moderate intellectual disabilities, which provided a 39% response rate. MEASURES: Self-efficacy and social support (from family, residential staff and peers with disabilities) for leisure physical activity were assessed using self-reported scales. Leisure physical activity participation was measured with a self-reported checklist of the frequency of leisure physical activity participation. ANALYSIS: Path analysis was conducted for the entire sample and was repeated for younger and older age groups. RESULTS: The hypothesized model fit the data from each group. Social support and self-efficacy predicted physical activity participation, and self-efficacy served as a mediator between social support and physical activity. Significant sources of social support differed between groups; among younger participants, social support from family predicted physical activity, whereas, for the older group, social support from staff and peers predicted physical activity. CONCLUSION: Self-efficacy and social support for leisure physical activity are related to leisure physical activity participation among adults with intellectual disabilities who are receiving supported-living services. The results provide information to guide health promotion programs for this group.

The relationship between active living and health-related quality of life: income as a moderator.

This study used a moderator model to examine the relationship between active living and the physical components of health-related quality of life [i.e. overall physical component of quality of life (PQOL), physical functioning and ability to fulfill physical role] among a randomly selected sample of rural residents (n = 407) from the Midwestern US. Results showed that active living was associated with greater increases in health-related quality of life for those reporting lower income. The effect size of the relationship between active living and the PQOL for the low-income group was over 2 times the effect size for the high-income group. For physical functioning, the effect size of active living for the low-income group was greater than 3 times the effect size for the high-income group. Although active living behaviors have been demonstrated to be less prevalent among those of low socioeconomic status, this group may have the most to gain from these activities. Findings highlight the need for increased and specifically targeted promotion of active living interventions.

Reliability and Accuracy of the AMP 331 for Activity Monitoring and Energy Expenditure Prediction in Young Adults.

BACKGROUND: A new triaxial accelerometer (AMP 331) provides a novel approach to understanding free-living activity through its ability to measure real time speed, cadence, and step length. This study examined the reliability and accuracy of the AMP 331, along with construction of prediction equations for oxygen consumption and energy cost. METHODS: Young adult volunteers (n = 41) wearing two AMP units walked and ran on a treadmill with energy cost data simultaneously collected through indirect calorimetry. RESULTS: Statistically significant differences exist in inter-AMP unit reliability for speed and step length and in accuracy between the AMP units and criterion measures for speed, oxygen consumption, and energy cost. However, the differences in accuracy for speed were very small during walking (≤ 0.16 km/h) and not clinically relevant. Prediction equations constructed for walking oxygen uptake and energy expenditure demonstrated R2 between 0.76 to 0.90 and between subject deviations were 1.53 mL O2 · kg-1 · min-1 and 0.43 kcal/min. CONCLUSIONS: In young adults, the AMP 331 is acceptable for monitoring walking speeds and the output can be used in predicting energy cost during walking but not running.