Paul McCrorie

Combining GPS, GIS, and accelerometry to explore the physical activity and environment relationship in children and young people - a review

The environment has long been associated with physical activity engagement, and recent developments in technology have resulted in the ability to objectively quantify activity behaviours and activity context. This paper reviews studies that have combined Global Positioning Systems (GPS), Geographic Information Systems (GIS) and accelerometry to investigate the PA-environment relationship in children and young people (5-18 years old). Literature searches of the following bibliographic databases were undertaken: Sportdiscus, Medline, Embase, CINAHL, Psychinfo and Applied Social Sciences Index and Abstracts (ASSIA). Fourteen studies met the inclusion criteria, and covered topics including greenspace use, general land use, active travel, and the built environment. Studies were largely cross-sectional and took place across developed countries (UK, USA, Canada, New Zealand, and Australia). Findings suggest that roads and streets, school grounds, and the home location are important locations for total PA, and moderate to vigorous PA (MVPA). The relationship between greenspace was positive, however, multiple definitions and outcome measures add complexity to the results. MVPA was more likely in those exposed to higher levels of greenspace compared to sedentary individuals. Total MVPA time in greenspace is low, but when framed as a proportion of the total can be quite high. Domestic gardens may be an important area for higher intensity activity.Researchers are encouraged to show transparency in their methods. As a relatively new area of research, with ever-evolving technology, future work is best placed in developing novel, but robust, methods to investigate the PA and environment relationship. Further descriptive work is encouraged to build on a small but increasing knowledge base; however, longitudinal studies incorporating seasonal/weather variation would also be extremely beneficial to elicit some of the nuances associated with land use. A greater understanding of geographic variation (i.e. within and between countries), as well as urban/suburban and rural dwelling is welcomed, and future work should also include the investigation of psycho-social health as an outcome, as well as differences in socio-economic status, sex and adiposity.

Step accumulation per minute epoch is not the same as cadence for free-living adults

PURPOSE The term cadence has been used interchangeably to describe both the rate of stepping and the number of steps in a minute epoch. This is only strictly true if walking is continuous within that epoch. This study directly compared these two outcomes in minute epochs of data from free-living adults to assess the scale of any difference between them. METHODS A convenience sample of healthy adults wore an activPAL activity monitor for 7 d. The event record output of the activPAL, providing the start time and duration of each stride to the nearest 0.1 s, was used to calculate step accumulation (number of steps), duration of walking, and cadence (number of steps/duration of walking) for each minute of measurement. RESULTS Data from 117 individuals (78 females; mean age, 46 ± 16 yr; mean body mass index, 24.9 ± 3.7 kg·m-2) were analyzed. Twenty-one percent of minutes (n = 310d-1) contained walking. The distribution (most minutes fewer than 40 steps per minute) and mean (34 ± 9 steps per minute) of step accumulation were very different from that of cadence (most minutes between 60 and 100 steps per minute; mean, 76 ± 6 steps per minute). Only 12% of minutes with stepping were walked continuously, whereas 69% of minutes with stepping contained less than 30 s of walking. This is key to the difference between step accumulation and cadence, and means that cadence cannot be reconstructed from step accumulation without also knowing the duration that was walked. CONCLUSION Step accumulation, the number of steps in a fixed period, and cadence, the rate of stepping while walking, are not interchangeable outcome measures. It is vitally important that unambiguous terminology is used to describe the rate of stepping so that the outcomes of studies can be correctly interpreted.

The validity of the Youth Physical Activity Questionnaire in 12–13-year-old Scottish adolescents

Background The development of accurate methods to measure health-behaviours forms an integral component in behavioural epidemiology. Population surveillance of physical activity often relies on self/proxy reported questionnaires due to cost and relative ease of administration. The aim of this study was to examine the criterion validity and measurement agreement between the Youth Physical Activity Questionnaire (YPAQ) and accelerometry before being included in a Scotland-wide study. Methods Forty four participants (12–13 years old; 61% girls) completed the YPAQ following 7 days wearing the Actigraph GT3X+. Mean moderate-to-vigorous physical activity (MVPA) per day was derived from YPAQ and accelerometer and validity was assessed using Spearmans correlation; Bland-Altman plots examined absolute agreement between methods. Results Pearsons and Spearman’s correlations between YPAQ and accelerometer were r = 0.47 and rs = 0.39 (p<0.01) respectively. The YPAQ over reported mean MVPA by 25.6 ± 50.2 minutes (95% CI 10.4-40.9 minutes; p <0.001), with 95% limits of agreement of −72.69 minutes and + 123.99 minutes. Evidence of underreporting at lower levels of activity and over reporting at higher levels of activity was evident (Pearsons r=0.81), in addition to heteroscedasticity, where variances increased as MVPA increased. Conclusions Although a moderate correlation between the two methods was apparent, the YPAQ should not be used interchangeably with accelerometry. The YPAQ does demonstrate a reasonable ability to rank MVPA, although it tends to under-report lower levels and over-report higher levels. This, and other administering factors, should be taken into consideration if being used for group or individual level analyses.

Walkability around primary schools and area deprivation across Scotland

BackgroundA number of studies based in the US, Canada, and Australia, have found evidence of associations between the built environment (BE) and mode of transport to school, and links between active travel and deprivation. Limited research in the UK compares potential BE supports for walking to school by area deprivation. Within this study, we gathered data on BE attributes previously linked to active travel, i.e., street/path connectivity, and dwelling density, created a composite ‘walkability score’ (WS) for areas around primary schools across urban Scotland, and explored whether poorer areas exhibit lower scores than more affluent areas, or vice versa. We consider this to be a novel approach as few studies have compared BE features by deprivation across a whole country.MethodsAddress and road/path maps were obtained and primary schools (N = 937) across mainland Scotland were mapped. Schools were attributed income deprivation scores (scores divided into quintiles (Q1: least deprived, Q5: most deprived)). Catchment area (CA) boundaries, i.e., the geographic area representing eligibility for local school attendance, were drawn around schools, and WS calculated for each CA. We compared mean WS by income quintile (ANOVA), for all local authorities (LAs) combined (N = 29), and separately for the four LAs with the greatest number of schools included in the analysis.ResultsFor all LAs combined, the least deprived quintile (Q1) showed a significantly lower WS (−0.61), than quintiles 3, 4 and 5 (Q2: −0.04 (non-sig), Q3: 0.38, Q4: 0.09, Q5: 0.18); while for Glasgow the second least deprived quintile (Q2) showed significantly higher WS (Q1: 1.35, Q2: 1.73), than middling (Q3: 0.18) and most deprived quintiles (Q4: 0.06, Q5: −0.10).ConclusionWS differ by deprivation with patterns varying depending on the spatial scale of the analysis. It is essential that less walkable areas are provided with the resources to improve opportunities to engage in active travel.

Objective assessment of intensity categorization of the previous day physical activity recall questionnaire in 11–13 year old children

The Previous Day Physical Activity Recall (PDPAR) self-report questionnaire asks children to categories their time in 30 min blocks under activity codes and activity intensity (ActInt). Text and visual descriptors of ActInt are used which include posture and stepping intensity. This study aimed to objectively examine postures and stepping activity associated with PDPAR ActInt. Forty-three (19M/24F) 11-13 year children completed the PDPAR and wore a physical activity monitor (8 d). Within 30 min blocks the % sitting/lying, standing and stepping, steps, cadence and sit-to-stand transitions (STS) were examined by PDPAR ActInt across and within all activity codes. Data (14 083 30 min blocks) showed from light to moderate ActInt lower sedentary time, higher standing and stepping time, steps, sit-to-stand transitions and cadence (all P < 0.001). Between moderate and hard ActInt, time sedentary was lower and time stepping, steps and STS higher (all P < 0.005). No significant differences between hard and very hard. There was a wide variation of activity levels between activity codes within ActInt. ActInt within the PDPAR was not used consistently between activity codes. However, over all codes children demonstrated that they could distinguish between light and moderate and in some objective measures between moderate and hard, but not between hard and very hard ActInt.

The prevalence of upright non-stepping time in comparison to stepping time in 11–13 year old school children across seasons

Evidence suggests that behaviours such as standing are beneficial for our health. Unfortunately, little is known of the prevalence of this state, its importance in relation to time spent stepping or variation across seasons. The aim of this study was to quantify, in young adolescents, the prevalence and seasonal changes in time spent upright and not stepping (UNSt(time)) as well as time spent upright and stepping (USt(time)), and their contribution to overall upright time (U(time)). Thirty-three adolescents (12.2 ± 0.3 y) wore the activPAL activity monitor during four school days on two occasions: November/December (winter) and May/June (summer). UNSt(time) contributed 60% of daily U(time) at winter (Mean = 196 min) and 53% at summer (Mean = 171 min); a significant seasonal effect, p < 0.001. USt(time) was significantly greater in summer compared to winter (153 min versus 131 min, p < 0.001). The effects in UNSt(time) could be explained through significant seasonal differences during the school hours (09:00-16:00), whereas the effects in USt(time) could be explained through significant seasonal differences in the evening period (16:00-22:00). Adolescents spent a greater amount of time upright and not stepping than they did stepping, in both winter and summer. The observed seasonal effects for both UNSt(time) and USt(time) provide important information for behaviour change intervention programs.

The Unanticipated Challenges Associated With Implementing an Observational Study Protocol in a Large-Scale Physical Activity and Global Positioning System Data Collection

Background Large-scale primary data collections are complex, costly, and time-consuming. Study protocols for trial-based research are now commonplace, with a growing number of similar pieces of work being published on observational research. However, useful additions to the literature base are publications that describe the issues and challenges faced while conducting observational studies. These can provide researchers with insightful knowledge that can inform funding proposals or project development work. Objectives In this study, we identify and reflectively discuss the unforeseen or often unpublished issues associated with organizing and implementing a large-scale objectively measured physical activity and global positioning system (GPS) data collection. Methods The SPACES (Studying Physical Activity in Children’s Environments across Scotland) study was designed to collect objectively measured physical activity and GPS data from 10- to 11-year-old children across Scotland, using a postal delivery method. The 3 main phases of the project (recruitment, delivery of project materials, and data collection and processing) are described within a 2-stage framework: (1) intended design and (2) implementation of the intended design. Results Unanticipated challenges arose, which influenced the data collection process; these encompass four main impact categories: (1) cost, budget, and funding; (2) project timeline; (3) participation and engagement; and (4) data challenges. The main unforeseen issues that impacted our timeline included the informed consent process for children under the age of 18 years; the use of, and coordination with, the postal service to deliver study information and equipment; and the variability associated with when participants began data collection and the time taken to send devices and consent forms back (1-12 months). Unanticipated budgetary issues included the identification of some study materials (AC power adapter) not fitting through letterboxes, as well as the employment of fieldworkers to increase recruitment and the return of consent forms. Finally, we encountered data issues when processing physical activity and GPS data that had been initiated across daylight saving time. Conclusions We present learning points and recommendations that may benefit future studies of similar methodology in their early stages of development.

Exploring children's perceptions of their local environment in relation to time spent outside

This study aims to understand how children perceive their environment, exploring the affordances children perceive to influence their physical activity (PA) behaviour when outside. Participants included boys and girls aged 10–12 years (n = 15) living in Scotland. Childrens visual and verbal representations of their perceived environment were analysed to assess environmental determinants of PA. The findings suggested that physical affordances that offer a sense of risk were important to childrens play spaces. Social affordances influenced where the children went in their environment and the features they utilised as part of play behaviour; strangers were considered threatening depending on whether the activity was recognised.

Comparison of two methods to assess physical activity prevalence in children: an observational study using a nationally representative sample of Scottish children aged 10–11 years

Objectives To describe the objectively measured levels of physical activity (PA) and sedentary time in a nationally representative sample of 10–11-year-old children, and compare adherence estimates to the UK PA guidelines using two approaches to assessing prevalence. Design Nationally representative longitudinal cohort study. Setting Scotland wide in partnership with the Growing up in Scotland (GUS) study. Data collection took place between May 2015 and May 2016. Participants The parents of 2402 GUS children were approached and 2162 consented to contact. Consenting children (n=1096) wore accelerometers for 8 consecutive days and 774 participants (427 girls, 357 boys) met inclusion criteria. Primary and secondary outcome measures Total PA (counts per minute, cpm); time spent sedentary and in moderate-to-vigorous PA (MVPA); proportion of children with ≥60 min MVPA on each day of wear (daily approach); proportion of children with ≥60 min of MVPA on average across days of wear (average approach)—presented across boys and girls, index of multiple deprivation and season. Results Mean PA level was 648 cpm (95% CI, 627 to 670). Children spent 7.5 hours (7.4–7.6) sedentary/day and 72.6 min (70.0–75.3) in MVPA/day. 11% (daily) and 68% (average) of children achieved the recommended levels of PA (P<0.05 for difference); a greater proportion of boys met the guidelines (12.5% vs 9.8%, NS; 75.9% vs 59.5%, P<0.001); guideline prevalence exhibited seasonal variation. No significant socioeconomic patterning existed across any outcome measure. Conclusions PA estimates are significantly influenced by the analytical method used to assess prevalence. This could have a substantial impact on the evaluation of interventions, policy objectives and public health investment. Existing guidelines, which focus on daily PA only may not further our understandings about the underlying construct itself. Gender differences exist within this age-group, suggesting greater investment, with particular consideration of seasonality, is needed for targeted intervention work in younger children.