Keith Brazendale

Classification of physical activity intensities using a wrist-worn accelerometer in 8–12-year-old children

Population‐specific accelerometer cut‐points are required to accurately determine the accumulation of physical activity of various intensities.

Measurement of physical activity in older adult interventions: a systematic review

Background Interventions to promote physical activity (PA) among older adults can positively impact PA behaviour and other health outcomes. Measurement of PA must be valid and reliable; however, the degree to which studies employ valid and reliable measures of PA is unclear. The purpose of this systematic review was to evaluate the measurement tools used in interventions to increase PA among older adults (65+ years), including both self-report measures and objective measures. In addition, the implications of these different measurement tools on study results were evaluated and discussed. Methods Four electronic research databases (MEDLINE, PsychINFO, Web of Science and EBSCO) were used to identify published intervention studies measuring the PA behaviour of adults over 65 years of age. Studies were eligible if: (1) PA was an outcome; (2) there was a comparison group and (3) the manuscript was published in English. Data describing measurement methods and properties were extracted and reviewed. Results Of the 44 studies included in this systematic review, 32 used self-report measures, 9 used objective measures and 3 used both measures. 29% of studies used a PA measure that had neither established validity nor reliability, and only 63% of measures in the interventions had established both validity and reliability. Only 57% of measures had population-specific reliability and 66% had population-specific validity. Conclusions A majority of intervention studies to help increase older adult PA used self-report measures, even though many have little evidence of validity and reliability. We recommend that future researchers utilise valid and reliable measures of PA with well-established evidence of psychometric properties such as hip-accelerometers and the Community Health Activities Model Program for Seniors (CHAMPS) Physical Activity Questionnaire for Older Adults.

Maximizing children's physical activity using the LET US Play principles

BACKGROUND Staff in settings that care for children struggle to implement standards designed to promote moderate-to-vigorous physical activity (MVPA), suggesting a need for effective strategies to maximize the amount of time children spend in MVPA during scheduled PA opportunities. The purpose of this study was to compare the MVPA children accumulate during commonly played games delivered in their traditional format versus games modified according to the LET US Play principles. METHODS Children (K-5th) participated in 1-hour PA sessions delivered on non-consecutive days (summer 2014). Using a randomized, counterbalanced design, one of the six games was played for 20min using either traditional rules or LET US Play followed by the other strategy with a 10min break in between. Physical activity was measured via accelerometry. Repeated-measures, mixed-effects regression models were used to estimate differences in percent of time spent sedentary and in MVPA. RESULTS A total of 267 children (age 7.5years, 43% female, 29% African American) participated in 50, 1-hour activity sessions. Games incorporating LET US Play elicited more MVPA from both boys and girls compared to the same games with traditional rules. For boys and girls, the largest MVPA difference occurred during tag games (+20.3%). The largest reduction in the percent of time sedentary occurred during tag games (boys -27.7%, girls -32.4%). Overall, the percentage of children meeting 50% time in MVPA increased in four games (+18.7% to +53.1%). CONCLUSION LET US Play led to greater accumulation of MVPA for boys and girls, and can increase the percent of children attaining the 50% of time in MVPA standard.

Equating accelerometer estimates among youth: The Rosetta Stone 2

OBJECTIVES Different accelerometer cutpoints used by different researchers often yields vastly different estimates of moderate-to-vigorous intensity physical activity (MVPA). This is recognized as cutpoint non-equivalence (CNE), which reduces the ability to accurately compare youth MVPA across studies. The objective of this research is to develop a cutpoint conversion system that standardizes minutes of MVPA for six different sets of published cutpoints. DESIGN Secondary data analysis. METHODS Data from the International Childrens Accelerometer Database (ICAD; Spring 2014) consisting of 43,112 Actigraph accelerometer data files from 21 worldwide studies (children 3-18 years, 61.5% female) were used to develop prediction equations for six sets of published cutpoints. Linear and non-linear modeling, using a leave one out cross-validation technique, was employed to develop equations to convert MVPA from one set of cutpoints into another. Bland Altman plots illustrate the agreement between actual MVPA and predicted MVPA values. RESULTS Across the total sample, mean MVPA ranged from 29.7MVPAmind(-1) (Puyau) to 126.1MVPAmind(-1) (Freedson 3 METs). Across conversion equations, median absolute percent error was 12.6% (range: 1.3 to 30.1) and the proportion of variance explained ranged from 66.7% to 99.8%. Mean difference for the best performing prediction equation (VC from EV) was -0.110mind(-1) (limits of agreement (LOA), -2.623 to 2.402). The mean difference for the worst performing prediction equation (FR3 from PY) was 34.76mind(-1) (LOA, -60.392 to 129.910). CONCLUSIONS For six different sets of published cutpoints, the use of this equating system can assist individuals attempting to synthesize the growing body of literature on Actigraph, accelerometry-derived MVPA.

Are We There Yet? Compliance with Physical Activity Standards in YMCA Afterschool Programs

BACKGROUND In 2011, the YMCA of the United States adopted physical activity standards for all their afterschool programs (ASPs), which call for children to accumulate 30 minutes of moderate-to-vigorous physical activity (MVPA) while attending YMCA ASPs. The extent to which youth attending YMCA ASPs achieve this standard is unknown. METHODS Using a cluster-stratified design, 20 ASPs were sampled from all YMCA-operated ASPs across South Carolina (N = 102). ASPs were visited on four unannounced, nonconsecutive weekdays. Accelerometer-derived minutes spent in MVPA were dichotomized to ≥30 min/d of MVPA and <30 min/d of MVPA. Program characteristics were measured through document review and direct observation and compared to MVPA levels using random-effects quantile regression. RESULTS Boys (n = 607) and girls (n = 475) accumulated a median of 25.3 and 17.1 min/d of MVPA, respectively, which translated into 33% (range 6.2%-67.3%) and 17% (0%-42.6%) achieving the 30 min/d of MVPA standard, respectively. Increase in time scheduled for activity (10.7-11.7 min/d of MVPA), limited sedentary choices during activity time (6.9-8.9 min/d of MVPA), and staff activity-promotion training (4.8-7.9 min/d of MVPA) were associated with higher accumulated minutes of MVPA for boys and girls. Program revenue, percent activity structure that was for free play, and indoor/outdoor space were inconsistently related to meeting the MVPA standard. CONCLUSIONS Modifiable programmatic structures were associated with higher amounts of MVPA. These findings suggest that simple programmatic changes could help ASPs to achieve the MVPA standard, regardless of infrastructure or finances.

Physical activity outcomes in afterschool programs: A group randomized controlled trial.

INTRODUCTION Afterschool programs (ASPs) across the US are working towards achieving the standard of all children accumulating 30min of moderate-to-vigorous physical activity (MVPA) during program time. This study describes the two-year impact of an intervention designed to assist ASPs meeting the 30min/day MVPA standard. METHODS Using a two-year delayed treatment, group randomized controlled trial, 20 ASPs serving ~1700 children/year (6-12yrs) were randomized to either an immediate (n=10, baseline-2013 and 2yrs intervention fall-2013-to-spring-2015) or delayed group (n=10, baseline 2013-2014 and 1yr intervention fall-2014-to-spring-2015). The intervention, Strategies-To-Enhance-Practice (STEPs), focused on programming MVPA in the daily schedule, training of staff and leaders, and ongoing technical support/assistance. Accelerometry-derived proportion of children meeting the 30min/day MVPA standard was measured in the spring of each year. Mixed model logistic regressions were used to examine the change in the odds of achieving the MVPA standard. Analyses were conducted in 2015. Data were collected in one southeastern US state. RESULTS Immediate boys (n=677) and delayed girls (n=658) increased the percent achieving 30min MVPA/day from 35.9% to 47.0% (odds ratio [OR]=1.88, 95% CI 1.18-3.00) and 13.1% to 19.1% (OR=1.42, 95% CI 1.03-1.96). Immediate girls (n=613) and delayed boys (n=687) exhibited a nonsignificant increase from 19.1% to 21.6% (OR=1.20, 95% CI 0.84-1.72) and 29.0% to 31.3% (OR=1.13, 95%CI 0.80-1.58). CONCLUSIONS STEPs can have an impact on childrens MVPA and time spent sedentary, yet was unable to fully achieve the goal of all children accumulating 30minMVPA/day. Additional efforts are need to identify strategies ASPs can use to meet this important public health standard.

Process Evaluation of Making HEPA Policy Practice: A Group Randomized Trial.

This study examines the link between implementation of Strategies to Enhance Practice (STEPs) and outcomes. Twenty after-school programs (ASPs) participated in an intervention to increase children’s accumulation of 30 minutes/day of moderate to vigorous physical activity (MVPA) and quality of snacks served during program time. Outcomes were measured via accelerometer (MVPA) and direct observation (snacks). STEPs implementation data were collected via document review and direct observation. Based on implementation data, ASPs were divided into high/low implementers. Differences between high/low implementers’ change in percentage of boys accumulating 30 minutes/day of MVPA were observed. There was no difference between high/low implementers for girls. Days fruits and/or vegetables and water were served increased in the high/low implementation groups, while desserts and sugar-sweetened beverages decreased. Effect sizes (ES) for the difference in changes between the high and low group ranged from low (ES = 0.16) to high (ES = 0.97). Higher levels of implementation led to increased MVPA for boys, whereas girls MVPA benefited from the intervention regardless of high/low implementation. ESs of the difference between high/low implementers indicate that increased implementation of STEPs increases days healthier snacks are served. Programs in the high-implementation group implemented a variety of STEPs strategies, suggesting local adoption/adaptation is key to implementation.

Wasting Our Time? Allocated Versus Accumulated Physical Activity in Afterschool Programs

BACKGROUND Afterschool programs (ASPs) can provide opportunities for children to accumulate moderate-to-vigorous physical activity (MVPA). The optimal amount of time ASPs should allocate for physical activity (PA) on a daily basis to ensure children achieve policy-stated PA recommendations remains unknown. METHODS Children (n = 1248, 5 to 12 years) attending 20 ASPs wore accelerometers up to 4 nonconsecutive week days for the duration of the ASPs during spring 2013 (February-April). Daily schedules were obtained from each ASP. RESULTS Across 20 ASPs, 3 programs allocated ≤ 30min, 5 approximately 45 min, 4 60 min, 4 75 min, and 4 ≥ 105 min for PA opportunities daily (min·d-1). Children accumulated the highest levels of MVPA in ASPs that allocated ≥ 60 min·d-1 for PA opportunities (24.8-25.1 min·d-1 for boys and 17.1-19.4 min·d-1 for girls) versus ASPs allocating ≤ 45 min·d-1 for PA opportunities (19.7 min·d-1 and 15.6 min·d-1 for boys and girls, respectively). There were no differences in the amount of MVPA accumulated by children among ASPs that allocated 60 min·d-1 (24.8 min·d-1 for boys and 17.1 min·d-1 for girls), 75 min·d-1 (25.1 min·d-1 for boys and 19.4 min·d-1 for girls) or ≥ 105 min·d-1 (23.8 min·d-1 for boys and 17.8 min·d-1 for girls). Across ASPs, 26% of children (31% for boys and 14% for girls) met the recommended 30 minutes of MVPA. CONCLUSIONS Allocating more than 1 hour of PA opportunities is not associated with an increase in MVPA during ASPs. Allocating 60 min·d-1, in conjunction with enhancing PA opportunities, can potentially serve to maximize childrens accumulation of MVPA during ASPs.

Choosing between responsive-design websites versus mobile apps for your mobile behavioral intervention: presenting four case studies

Both mobile apps and responsive-design websites (web apps) can be used to deliver mobile health (mHealth) interventions, but it can be difficult to discern which to use in research. The goal of this paper is to present four case studies from behavioral interventions that developed either a mobile app or a web app for research and present an information table to help researchers determine which mobile option would work best for them. Four behavioral intervention case studies (two developed a mobile app, and two developed a web app) presented include time, cost, and expertise. Considerations for adopting a mobile app or a web app—such as time, cost, access to programmers, data collection, security needs, and intervention components— are presented. Future studies will likely integrate both mobile app and web app modalities. The considerations presented here can help guide researchers on which platforms to choose prior to starting an mHealth intervention.

Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis

BackgroundAlthough the scientific community has acknowledged modest improvements can be made to weight status and obesogenic behaviors (i.e., physical activity, sedentary/screen time, diet, and sleep) during the school year, studies suggests improvements are erased as elementary-age children are released to summer vacation. Emerging evidence shows children return to school after summer vacation displaying accelerated weight gain compared to the weight gained occurring during the school year. Understanding how summer days differ from when children are in school is, therefore, essential.DiscussionThere is limited evidence on the etiology of accelerated weight gain during summer, with few studies comparing obesogenic behaviors on the same children during school and summer. For many children, summer days may be analogous to weekend days throughout the school year. Weekend days are often limited in consistent and formal structure, and thus differ from school days where segmented, pre-planned, restrictive, and compulsory components exist that shape obesogenic behaviors. The authors hypothesize that obesogenic behaviors are beneficially regulated when children are exposed to a structured day (i.e., school weekday) compared to what commonly occurs during summer. This is referred to as the ‘Structured Days Hypothesis’ (SDH). To illustrate how the SDH operates, this study examines empirical data that compares weekend day (less-structured) versus weekday (structured) obesogenic behaviors in U.S. elementary school-aged children. From 190 studies, 155 (~80%) demonstrate elementary-aged children’s obesogenic behaviors are more unfavorable during weekend days compared to weekdays.ConclusionIn light of the SDH, consistent evidence demonstrates the structured environment of weekdays may help to protect children by regulating obesogenic behaviors, most likely through compulsory physical activity opportunities, restricting caloric intake, reducing screen time occasions, and regulating sleep schedules. Summer is emerging as the critical period where childhood obesity prevention efforts need to be focused. The SDH can help researchers understand the drivers of obesogenic behaviors during summer and lead to innovative intervention development.