Robert J. Noonan

Wear compliance and activity in children wearing wrist and hip mounted accelerometers

PURPOSE This study aimed to 1) explore childrens compliance to wearing wrist- and hip-mounted accelerometers, 2) compare childrens physical activity (PA) derived from raw accelerations of wrist and hip, and 3) examine differences in raw and counts PA measured by hip-worn accelerometry. METHODS One hundred and twenty-nine 9- to 10-yr-old children wore a wrist-mounted GENEActiv accelerometer (GAwrist) and a hip-mounted ActiGraph GT3X+ accelerometer (AGhip) for 7 d. Both devices measured raw accelerations, and the AGhip also provided count-based data. RESULTS More children wore the GAwrist than those from the AGhip regardless of wear time criteria applied (P < 0.001-0.035). Raw data signal vector magnitude (r = 0.68), moderate PA (MPA) (r = 0.81), vigorous PA (VPA) (r = 0.85), and moderate-to-vigorous PA (MVPA) (r = 0.83) were strongly associated between devices (P < 0.001). GAwrist signal vector magnitude (P = 0.001), MPA (P = 0.037), VPA (P = 0.002), and MVPA (P = 0.016) were significantly greater than those from the AGhip. According to GAwrist raw data, 86.9% of children engaged in at least 60 min · d(-1) of MVPA, compared with 19% for AGhip. ActiGraph MPA (raw) was 42.00 ± 1.61 min · d(-1) compared with 35.05 ± 0.99 min · d(-1) (counts) (P = 0.02). ActiGraph VPA was 7.59 ± 0.46 min · d(-1) (raw) and 37.06 ± 1.85 min · d(-1) (counts; P = 0.19). CONCLUSIONS In children, accelerometer wrist placement promotes superior compliance than the hip. Raw accelerations were significantly higher for GAwrist compared with those for AGhip possibly because of placement location and technical differences between devices. AGhip PA calculated from raw accelerations and counts differed substantially, demonstrating that PA outcomes derived from cut points for raw output and counts cannot be directly compared.

Comparison of children's free-living physical activity derived from wrist and hip raw accelerations during the segmented week

ABSTRACT This study assessed children’s physical activity (PA) levels derived from wrist-worn GENEActiv and hip-worn ActiGraph GT3X+ accelerometers and examined the comparability of PA levels between the two devices throughout the segmented week. One hundred and twenty-nine 9–10-year-old children (79 girls) wore a GENEActiv (GAwrist) and ActiGraph GT3X+ (AGhip) accelerometer on the left wrist and right hip, respectively, for 7 days. Mean minutes of light PA (LPA) and moderate-to-vigorous PA (MVPA) per weekday (whole-day, before-school, school and after-school) and weekend day (whole-day, morning and afternoon–evening) segments were calculated, and expressed as percentage of segment time. Repeated measures analysis of variance examined differences in LPA and MVPA between GAwrist and AGhip for each time segment. Bland–Altman plots assessed between-device agreement for LPA and MVPA for whole weekday and whole weekend day segments. Correlations between GAwrist and AGhip were weak for LPA (r = 0.18–0.28), but strong for MVPA (r = 0.80–0.86). LPA and MVPA levels during all weekday and weekend day segments were significantly higher for GAwrist than AGhip (p < 0.001). The largest inter-device percent difference of 26% was observed in LPA during the school day segment. Our data suggest that correction factors are needed to improve raw PA level comparability between GAwrist and AGhip.

Cross-sectional associations between high-deprivation home and neighbourhood environments, and health-related variables among Liverpool children

Objectives (1) To investigate differences in health-related, home and neighbourhood environmental variables between Liverpool children living in areas of high deprivation (HD) and medium-to-high deprivation (MD) and (2) to assess associations between these perceived home and neighbourhood environments and health-related variables stratified by deprivation group. Design Cross-sectional study. Setting 10 Liverpool primary schools in 2014. Participants 194 children aged 9–10 years. Main outcome measures Health-related variables (self-reported physical activity (PA) (Physical Activity Questionnaire for Older Children, PAQ-C), cardiorespiratory fitness, body mass index (BMI) z-scores, waist circumference), home environment variables: (garden/backyard access, independent mobility, screen-based media restrictions, bedroom media) and neighbourhood walkability (Neighbourhood Environment Walkability Scale for Youth, NEWS-Y). Explanatory measures Area deprivation. Results There were significant differences between HD and MD childrens BMI z-scores (p<0.01), waist circumference (p<0.001) and cardiorespiratory fitness (p<0.01). HD children had significantly higher bedroom media availability (p<0.05) and independent mobility scores than MD children (p<0.05). MD children had significantly higher residential density and neighbourhood aesthetics scores, and lower crime safety, pedestrian and road traffic safety scores than HD children, all of which indicated higher walkability (p<0.01). HD childrens BMI z-scores (β=−0.29, p<0.01) and waist circumferences (β=−0.27, p<0.01) were inversely associated with neighbourhood aesthetics. HD childrens PA was negatively associated with bedroom media (β=−0.24, p<0.01), and MD childrens PA was positively associated with independent mobility (β=0.25, p<0.01). MD childrens independent mobility was inversely associated with crime safety (β=−0.28, p<0.01) and neighbourhood aesthetics (β=−0.24, p<0.05). Conclusions Children living in HD areas had the least favourable health-related variables and were exposed to home and neighbourhood environments that are unconducive to health-promoting behaviours. Less access to bedroom media equipment and greater independent mobility were strongly associated with higher PA in HD and MD children, respectively. Facilitating independent mobility and encouraging outdoor play may act as effective strategies to enhance PA levels and reduce sedentary time in primary school-aged children.

Parental perceptions on childrens out-of-school physical activity and family-based physical activity

ABSTRACT This study explored parents’ physical activity (PA) knowledge and perceptions of children’s out-of-school PA to formatively contribute to a family-based intervention design. Eleven telephone interviews were conducted with parents of children aged 10–11 years. Child and parent data were triangulated and family case studies were written. Most parents were unaware of the UK child PA guidelines and whether their child achieved the guidelines daily. PA for many parents was attributed to healthy weight status, and the neighbourhood environment was perceived as unconducive to children’s outdoor play which consequently increased the attractiveness of adult supervised organized activities. Consulting with parents in a formative sense prior to familial PA intervention facilitates intervention content to be aligned with family-specific perceptions and needs, and offers opportunities to communicate the relevance of programs to parents. This may aid subsequent intervention recruitment and engagement.

Is there a deprivation and maternal education gradient to child obesity and moderate‐to‐vigorous physical activity? Findings from the Millennium Cohort Study

The primary aim was to examine associations between individual‐level and area‐level measures of socioeconomic status (SES) and different measures of overweight/obesity in 7‐year‐old English children. A secondary aim was to examine associations between individual‐level and area‐level measures of SES and moderate‐to‐vigorous intensity physical activity (MVPA).

Fitness, Fatness and Active School Commuting among Liverpool Schoolchildren

This study investigated differences in health outcomes between active and passive school commuters, and examined associations between parent perceptions of the neighborhood environment and active school commuting (ASC). One hundred-ninety-four children (107 girls), aged 9–10 years from ten primary schools in Liverpool, England, participated in this cross-sectional study. Measures of stature, body mass, waist circumference and cardiorespiratory fitness (CRF) were taken. School commute mode (active/passive) was self-reported and parents completed the neighborhood environment walkability scale for youth. Fifty-three percent of children commuted to school actively. Schoolchildren who lived in more deprived neighborhoods perceived by parents as being highly connected, unaesthetic and having mixed land-use were more likely to commute to school actively (p < 0.05). These children were at greatest risk of being obese and aerobically unfit (p < 0.01). Our results suggest that deprivation may explain the counterintuitive relationship between obesity, CRF and ASC in Liverpool schoolchildren. These findings encourage researchers and policy makers to be equally mindful of the social determinants of health when advocating behavioral and environmental health interventions. Further research exploring contextual factors to ASC, and examining the concurrent effect of ASC and diet on weight status by deprivation is needed.

Predictors of segmented school day physical activity and sedentary time in children from a northwest England low-income community

Background: Schools have been identified as important settings for health promotion through physical activity participation, particularly as children are insufficiently active for health. The aim of this study was to investigate the child and school-level influences on children′s physical activity levels and sedentary time during school hours in a sample of children from a low-income community; Methods: One hundred and eighty-six children (110 boys) aged 9–10 years wore accelerometers for 7 days, with 169 meeting the inclusion criteria of 16 h∙day−1 for a minimum of three week days. Multilevel prediction models were constructed to identify significant predictors of sedentary time, light, and moderate to vigorous physical activity during school hour segments. Child-level predictors (sex, weight status, maturity offset, cardiorespiratory fitness, physical activity self-efficacy, physical activity enjoyment) and school-level predictors (number on roll, playground area, provision score) were entered into the models; Results: Maturity offset, fitness, weight status, waist circumference-to-height ratio, sedentary time, moderate to vigorous physical activity, number of children on roll and playground area significantly predicted physical activity and sedentary time; Conclusions: Research should move towards considering context-specific physical activity and its correlates to better inform intervention strategies.

Converting between estimates of moderate-to-vigorous physical activity derived from raw accelerations measured at the wrist and from ActiGraph counts measured at the hip: the Rosetta Stone

ABSTRACT The ability to compare published group-level estimates of objectively measured moderate-to-vigorous physical activity (MVPA) across studies continues to increase in difficulty. The objective of this study was to develop conversion equations and demonstrate their utility to compare estimates of MVPA derived from the wrist and hip. Three studies of youth (N = 232, 9-12yrs, 50% boys) concurrently wore a hip-worn ActiGraph and a wrist-worn GENEActiv for 7-days. ActiGraph hip count data were reduced using four established cutpoints. Wrist accelerations were reduced using the Hildebrand MVPA 200 mg threshold. Conversion equations were developed on a randomly selected subsample of 132 youth. Equations were cross-validated and absolute error, absolute percent error, and modified Bland-Altman plots were evaluated for conversion accuracy. Across equations R2adj was 0.51–0.56 with individual-level absolute error in minutes ranging from 7 (wrist-to-hip Puyau) to 14.5 minutes (wrist-to-hip Freedson 3MET) and absolute percent differences ranging from 13.9%-24.5%. Group-level cross-validation to convert hip-to-wrist MVPA resulted in average absolute percent errors ranging from 3.1%-4.9%. Conversion of wrist-to-hip MVPA resulted in average absolute percent errors ranging from 3.0%-10.0%. We recommend the use of these equations to compare published estimates of MVPA between the wear-site cut-point combinations presented.

Comparability of children’s sedentary time estimates derived from wrist worn GENEActiv and hip worn ActiGraph accelerometer thresholds

OBJECTIVES To examine the comparability of childrens free-living sedentary time (ST) derived from raw acceleration thresholds for wrist mounted GENEActiv accelerometer data, with ST estimated using the waist mounted ActiGraph 100count·min-1 threshold. DESIGN Secondary data analysis. METHOD 108 10-11-year-old children (n=43 boys) from Liverpool, UK wore one ActiGraph GT3X+ and one GENEActiv accelerometer on their right hip and left wrist, respectively for seven days. Signal vector magnitude (SVM; mg) was calculated using the ENMO approach for GENEActiv data. ST was estimated from hip-worn ActiGraph data, applying the widely used 100count·min-1 threshold. ROC analysis using 10-fold hold-out cross-validation was conducted to establish a wrist-worn GENEActiv threshold comparable to the hip ActiGraph 100count·min-1 threshold. GENEActiv data were also classified using three empirical wrist thresholds and equivalence testing was completed. RESULTS Analysis indicated that a GENEActiv SVM value of 51mg demonstrated fair to moderate agreement (Kappa: 0.32-0.41) with the 100count·min-1 threshold. However, the generated and empirical thresholds for GENEActiv devices were not significantly equivalent to ActiGraph 100count·min-1. GENEActiv data classified using the 35.6mg threshold intended for ActiGraph devices generated significantly equivalent ST estimates as the ActiGraph 100count·min-1. CONCLUSIONS The newly generated and empirical GENEActiv wrist thresholds do not provide equivalent estimates of ST to the ActiGraph 100count·min-1 approach. More investigation is required to assess the validity of applying ActiGraph cutpoints to GENEActiv data. Future studies are needed to examine the backward compatibility of ST data and to produce a robust method of classifying SVM-derived ST.

Evaluation of a Pilot School-Based Physical Activity Clustered Randomised Controlled Trial—Active Schools: Skelmersdale

Schools are key environments in which physical activity (PA) can be promoted. Various strategies and opportunities should be used to engage children in PA within schools. The aim of this study was to evaluate the effectiveness of the multi-component Active Schools: Skelmersdale (AS:Sk) pilot intervention on children’s PA and sedentary time (ST). The AS:Sk intervention was implemented for eight weeks in four schools with three control schools continuing normal practice. It consisted of eight components: active breaks, bounce at the bell, ‘Born To Move’ videos, Daily Mile or 100 Mile Club, playground activity challenge cards, physical education teacher training, newsletters, and activity homework. Child-level measures were collected at baseline and follow-up, including objectively measured PA. After accounting for confounding variables, the intervention had a significant effect on school day ST which was significantly less for the intervention children by 9 min per day compared to the control group. The AS:Sk pilot intervention was effective in reducing school day ST but significant changes in PA were negligible. To increase the efficacy of the current and future school-based interventions, authors should focus on implementation and process evaluations to better understand how schools are implementing intervention components.