Validity of SC-StepRx pedometer-derived moderate and vigorous physical activity during treadmill walking and running in a heterogeneous sample of children and youth

Correlates of Physical Activity in Children from Families Speaking Non-official Languages at Home: a Multi-site Canadian Study

BACKGROUND

Children from families speaking a non-official language at home may be particularly at risk for low physical activity (PA), underscoring a need to investigate correlates of PA in this subpopulation.

METHODS

We recruited 478 children in 37 schools stratified by area-level socioeconomic status (SES) and type of urbanization within three regions of Canada. Steps/day were measured using SC-StepRx pedometers. We assessed potential social-ecological correlates with child and parent surveys. We used gender-stratified linear mixed models to examine the correlates of steps/day.

RESULTS

Outdoor time was the strongest correlate of boys' and girls' PA. Lower area-level SES was associated with less PA among boys, but outdoor time attenuated this difference. The strength of association between outdoor time and PA decreased with age in boys and increased with age in girls.

DISCUSSION

Outdoor time was the most consistent correlate of PA. Future interventions should promote outdoor time and address socioeconomic disparities.

Nine-axis inertial measurement unit output discriminates activities of varying intensity in the dog

OBJECTIVE

To explore relationships between 9-axis inertial measurement unit (IMU) output and activities of varying intensity in dogs of various sizes.

ANIMALS

20 healthy, agility course-trained dogs of various ages and sizes.

PROCEDURES

Height, weight, body condition score, age, length from IMU to the ischium, and height of IMU to the floor were recorded. Dogs performed a series of activities (rest, walk, trot, and agility course) while wearing the IMU device. IMU and video output were reviewed by independent investigators. Correlations and multiple regression models were used to explore relationships between independent variables and IMU output.

RESULTS

Calibration demonstrated excellent correlation and concordance between IMUs (intraclass correlation > 0.9) and that the IMUs reliably measured a known acceleration (gravity at rest). Resultant vector magnitude {sqrt[(x^2) + (y^2) + (z^2)]} normalized to body size was calculated from the data. IMU output clearly discriminates between activities of varying intensity in the dog.

CLINICAL RELEVANCE

The inability to accurately measure chronic pain is a barrier to the development of new, or critical evaluation of, therapeutics. Activity monitors (AM) may be the ideal diagnostic target since they are small and provide objective data that can be collected while the pet remains in its natural environment. These results demonstrate the concurrent and predictive validity of the IMU tested. Our long-range goal is to validate an open-source algorithm for the IMU so activity in a pet's natural environment can be used as an outcome measure in future studies.

Pedometer Efficacy for Clinical Care in Pediatric Cardiology

BACKGROUND

Physical activity is essential to the long-term health of children living with cardiac disease. The simplicity and cost of pedometers make them an attractive alternative to accelerometers for monitoring the physical activity behaviors of these children. This study compared measures obtained from commercial-grade pedometers and accelerometers.

METHODS

Pediatric cardiology outpatients (n = 41, mean age = 8.4 [3.7] y, 61% female) wore a pedometer and accelerometer daily for 1 week. Step counts and minutes of moderate to vigorous physical activity were compared between devices, accounting for age group, sex, and diagnostic severity, using univariate analysis of variance.

RESULTS

While pedometer data were significantly correlated with accelerometers (r > .74, P < .001), measurements obtained were significantly different between devices. Overall, pedometers overestimated physical activity data. The overestimation of moderate to vigorous physical activity was significantly less among adolescents than younger age groups (P < .01, ηp2=.38). For step counts, there was a significant age by sex interaction observed where preschool and adolescent males tended to have greater differences between accelerometer and step count data than females (P < .01, ηp2=.33). Differences between devices were not associated with severity of diagnosis.

CONCLUSIONS

The distribution of pedometers in a pediatric outpatient clinic was feasible, yet the data collected significantly overestimated physical activity, especially among younger children. Practitioners who want to introduce objective measurements as part of their physical activity counseling practice should use pedometers to monitor individual changes in physical activity and consider patient age before administering these devices for clinical care.

Sex-specific correlates of metabolic syndrome risk in college-aged young adults

Objective: To identify the sex-specific prevalence of metabolic syndrome (MetS) risk factors and their physiological, psychosocial, and behavioral correlates in a college-aged population. Participants and methods: Cross-sectional assessment of MetS risk factors and potential correlates occurred in 379 first-year students (aged 18.34 ± 0.49 years, 67.3% female). Multivariable linear regression assessed the relationships between potential correlates and continuous MetS risk scores, derived from principal component analysis. Results: MetS risk factors were present in 58.4% of females and 68.5% of males, with 2.4% and 3.2% having defined MetS. In females, percent body fat (β = 0.46, p < 0.001), stress (β = 0.12, p = 0.031), % kcal from sugar (β = 0.18, p = 0.001), and moderate-to-vigorous physical activity (β=-0.12, p = 0.036) were associated with risk score. Whereas, correlates in males included percent body fat (β = 0.54, p < 0.001), C-reactive protein (β = 0.15, p = 0.045), and AUDIT alcohol consumption score (β = 0.15, p = 0.033). Conclusion: The sex-specific prevalence of MetS risk factors and correlates suggest that primary prevention strategies on college campuses should also follow a sex-specific approach.

Body composition, physical fitness and physical activity in Mozambican children and adolescents living with HIV

INTRODUCTION

As a result of the effectiveness of antiretroviral drugs (ART), HIV/AIDS has become a chronic disease, which has enabled children living with HIV to reach adolescence and adulthood. However, the long exposure to both the disease and ART has caused undesirable effects that compromise the physiological functioning and the quality of life of the subjects.

OBJECTIVE

To determine the body composition, physical fitness and habitual physical activity of children and adolescents living with HIV on ART.

METHODS

A total of 79 subjects of both genders aged 8-14 years, living with HIV in ART, selected by convenience participated in the study. The subjects underwent anthropometric assessment, physical fitness assessment and physical activity assessment.

RESULTS

Relative to reference norms, the values of the anthropometric indicators fell below 50th percentile (height/age = 92.4%; BMI/age 72.2%; sum of skinfolds = 51.9%; arm circumference = 63.3%). The prevalence of "low height/age" and "low weight/age" was 34.9% and 9.3%, respectively for boys, and 27.9% and 11.1%, respectively for girls. With the exception of trunk flexibility (12.3%), most subjects were considered unfit in the physical fitness tests (abdominal resistance = 76.4%; handgrip strength = 75.4%; lower limb power = 66.4%). The percentage of subjects with insufficient physical activity was 45.5% for boys and 77.8% for girls. The values for all variables were consistently and significantly lower when compared with studies done in Mozambicans boys and girls without HIV+ from both urban and rural areas.

CONCLUSION

The subjects participants in the study living with HIV and undergoing ART had impaired growth, low physical fitness and low levels of habitual physical activity in relation to the reference values of their peers without HIV, which compromised their physiological functioning and their quality of life.

Physical activity and active transportation behaviour among rural, peri-urban and urban children in Kenya, Mozambique and Nigeria: The PAAT Study

Background

Physical activity (PA) is associated with numerous health benefits among children and youth. However, few studies have examined how active transportation (AT) and device-based measures of PA vary within and between countries in sub-Saharan Africa.

Purpose

This cross-sectional study sought to investigate the prevalence and correlates of AT and device-measured PA among children living in urban, peri-urban and rural areas in three African countries representing Eastern, Western and Southern regions of Africa.

Methods

3,205 participants (53.3% girls; 46.7% boys) aged 10–12 years were recruited in Kenya, Nigeria and Mozambique. Data were collected using a child questionnaire, a parent/guardian questionnaire and PiezoRx® pedometers. ANCOVA and binary logistic regression analyses were used to examine the correlates of AT and PA while controlling for gender, age, parent education and vehicle ownership.

Results

Participants accumulated an average of 45.6±23.5 min/day of moderate-to-vigorous physical activity (MVPA) and 11,215±4,273 steps/day. Kenyan and Mozambican children were significantly more active than their Nigerian counterparts (p<0.001). Only 23% met the MVPA guidelines of 60 min/day. 65.1% of participants engaged in AT to school (and 67.8% for the trip back home) with no gender differences. Living in a rural area, lower parent education, lower vehicle ownership and higher motorcycle ownership were associated with higher odds of AT. Other correlates of AT were country-specific. Girls accumulated less daily MVPA than boys in all countries. MVPA was positively associated with living in less urbanized areas in Nigeria and Mozambique. In Kenya, lower parental education and AT were associated with higher MVPA. Nigerian children’s daily MVPA decreased with age and the number of parent-perceived barriers to AT.

Conclusions

Majority of children engaged in AT, but still failed to meet MVPA recommendations. Most correlates of AT and PA were country-specific, suggesting that strategies to encourage both behaviours should be informed by local evidence.

Validity and reliability of the lederman Prenatal Self-Evaluation Questionnaire (PSEQ) in Brazil

Background

The Lederman Prenatal Self-Evaluation Questionnaire (PSEQ) is used to assess psychosocial adaptation to pregnancy, labor, childbirth, and maternity. The PSEQ is a tool used in various countries and has been translated into Portuguese; however, it needs to be validated in Brazil. This study aimed to analyze the validity and reliability of the PSEQ in Brazilian pregnant women.

Method

This methodological validity study investigated internal consistency and reliability using Cronbach’s alpha and intraclass correlation coefficients. Construct validity was assessed using Pearson’s correlation between domains and confirmatory factor analysis. To assess concurrent validity, Pearson’s correlation between the different domains of the PSEQ and Prenatal Psychosocial Profile-Portuguese Version (PPP-VP) was determined. The level of significance was set at 5%.

Results

This study included 399 pregnant women in the northeastern region of Brazil. The internal consistency and reliability of the total PSEQ score were high (Cronbach's alpha = 0.89; intraclass correlation coefficient = 0.95). Validity analysis showed positive and significant correlations between all PSEQ domains, ranging from 0.14 to 0.56. Confirmatory factor analysis demonstrated the following values of goodness of fit: RMSEA = 0.05, SRMR = 0.08, CFI = 0.61, χ²/df = 1.77. The discriminant and concurrent validities of the PSEQ were confirmed.

Conclusions

The Portuguese version of the PSEQ has adequate psychometric properties and is a valid and reliable tool to evaluate psychosocial adaptation to pregnancy in Brazilian pregnant women.

Predicting lying, sitting, walking and running using Apple Watch and Fitbit data

OBJECTIVES

This study's objective was to examine whether commercial wearable devices could accurately predict lying, sitting and varying intensities of walking and running.

METHODS

We recruited a convenience sample of 49 participants (23 men and 26 women) to wear three devices, an Apple Watch Series 2, a Fitbit Charge HR2 and iPhone 6S. Participants completed a 65 min protocol consisting of 40 min of total treadmill time and 25 min of sitting or lying time. The study's outcome variables were six movement types: lying, sitting, walking self-paced and walking/running at 3 metabolic equivalents of task (METs), 5 METs and 7 METs. All analyses were conducted at the minute level with heart rate, steps, distance and calories from Apple Watch and Fitbit. These included three different machine learning models: support vector machines, Random Forest and Rotation forest.

RESULTS

Our dataset included 3656 and 2608 min of Apple Watch and Fitbit data, respectively. Rotation Forest models had the highest classification accuracies for Apple Watch at 82.6%, and Random Forest models had the highest accuracy for Fitbit at 90.8%. Classification accuracies for Apple Watch data ranged from 72.6% for sitting to 89.0% for 7 METs. For Fitbit, accuracies varied between 86.2% for sitting to 92.6% for 7 METs.

CONCLUSION

This preliminary study demonstrated that data from commercial wearable devices could predict movement types with reasonable accuracy. More research is needed, but these methods are a proof of concept for movement type classification at the population level using commercial wearable device data.

Relationships Among Children's Independent Mobility, Active Transportation, and Physical Activity: A Multisite Cross-Sectional Study

PURPOSE

Children's independent mobility (IM) may facilitate both active transportation (AT) and physical activity (PA), but previous studies examining these associations were conducted in single regions that provided limited geographical variability.

METHOD

We recruited 1699 children (55.0% girls) in 37 schools stratified by level of urbanization and socioeconomic status in 3 regions of Canada: Ottawa, Trois-Rivières, and Vancouver. Participants wore a SC-StepRx pedometer for 7 days and completed a validated questionnaire from which we derived a 6-point IM index, the number of AT trips over a week, and the volume of AT to/from school (in kilometer per week). We investigated relationships among measures of IM, AT, and PA employing linear mixed models or generalized linear mixed models adjusted for site, urbanization, and socioeconomic status.

RESULTS

Each unit increase in IM was associated with 9% more AT trips, 19% higher AT volume, and 147 more steps per day, with consistent results across genders. Both measures of AT were associated with marginally higher PA when pooling boys' and girls' data. Children in Vancouver engaged in more AT. PA did not vary across site, urbanization, or socioeconomic status.

CONCLUSION

IM was associated with more AT and PA regardless of where children lived, underscoring a need for IM interventions.

Correlates of Children's Physical Activity: A Canadian Multisite Study

PURPOSE

To inform future physical activity (PA) interventions among children, we investigated the correlates of PA among 8- to 12-yr-olds in three regions of Canada: Ottawa, Trois-Rivières, and Vancouver.

METHODS

We recruited 1699 children (55.0% girls) in 37 schools located in urban, suburban, and rural areas that differed in socioeconomic status. Children wore a sealed SC-StepRx pedometer capable of measuring moderate- to vigorous-intensity physical activity (MVPA) for seven consecutive days. Children and one of their parents/guardians completed a questionnaire that captured multiple potential PA correlates. Publicly available data on weather and neighborhood walkability were obtained. Multiply-imputed gender-stratified linear mixed models were used to examine the correlates of daily step counts and MVPA while controlling for age, site, type of urbanization, and area-level socioeconomic status.

RESULTS

Each additional hour spent outdoors was associated with higher PA in boys (+769 steps per day; +3.7 min MVPA per day) and girls (+596 steps per day; +3.5 min·d). Boys' PA declined with age (-500 steps per day; -3.7 min·d). Boys were less active if they had a long-standing injury/illness (-1862 steps per day; -3.7 min·d) or their parents reported driving to work (-835 steps per day; -4.4 min·d), were worried about traffic (-982 steps per day; -6.4 min·d), or about other people in their neighborhood (-1250 steps per day). Girls speaking neither English nor French at home were less active (-620 steps per day; -3.7 min·d). In girls, each degree Celsius increase in morning temperature was associated with 77 additional steps per day, and each kilometer increase in active school travel distance was associated with 0.5 more MVPA minutes per day.

CONCLUSION

Consistent with previous studies, our results suggest that PA interventions should aim to increase outdoor time. The observed gender differences in PA correlates suggest the need for a gender-sensitized approach to PA promotion.

The Association Between PLAYfun and Physical Activity: A Convergent Validation Study

Purpose: The purpose of this study was to examine the convergent validity of the PLAYfun tool, a physical literacy-based measure of movement competence, by examining its association with objectively measured physical activity in a sample of children and youth. Method: Participants included 110 children between the ages of seven to 14 years attending a stratified random sample of 27 afterschool programs across the province of Ontario, Canada. The PLAYfun tool was administered to the participants on one occasion at their afterschool program and then they were asked to wear a pedometer for seven consecutive days to measure their physical activity levels. A series of multiple linear regression models were used to examine the association between PLAYfun scores and physical activity, while controlling for age, sex, and time of year (season) in which the data were collected. Results: On its own, the PLAYfun average score accounted for close to 13% of the variance in physical activity, R = .36, R² = .13, p < .001. The PLAYfun average score was also a significant independent predictor of physical activity, b (SE) = 145.98 (53.46), p < .01, when controlling for age, sex, and season in which the data were collected, R² = .30, F (4, 105) = 11.04, p < .001. Conclusion: Results from the present study indicate that the PLAYfun tool is a significant predictor of objectively measured physical activity, supporting the convergent validity of the tool.

Correlation of activity data in normal dogs to distance traveled

The objective of this study was to explore the mathematical relationships between independent variables (patient morphometrics and treadmill speed) and dependent variables (accelerometer or pedometer output) when evaluating data from accelerometers and pedometers in dogs. Twenty dogs took part in 3 randomized activities, consisting of exercise on a treadmill at 1.0, 1.5, and 2.0 m/s for a total distance of 1 km at each speed. Dogs simultaneously wore both an accelerometer and a pedometer. Statistical analysis used multiple regression models to discover the relationships between independent and dependent variables. A formula was developed to predict the distance traveled by a dog based on its morphometrics and activity monitor output. Shoulder height had stronger correlations to accelerometer and pedometer outputs than other morphometric variables. As shoulder height increased, all accelerometer and pedometer outputs decreased. As treadmill speed increased, both accelerometer and pedometer step counts decreased, while accelerometer activity counts increased. According to a formula derived to predict the total distance traveled using patient shoulder height and accelerometer or pedometer output, pedometer steps were the most accurate predictor of distance traveled. Accelerometer steps were less accurate when using the same model. Accelerometer activity counts did not reveal a meaningful predictive formula. The results of this study indicate that patient morphometrics and treadmill speed (as a measure of intensity) influenced accelerometer and pedometer data. The pedometer data more precisely and accurately estimated the distance traveled based on step counts and patient shoulder height. In normal dogs, accelerometer and pedometer steps may reasonably estimate distance traveled.

Walking on Water-A Natural Experiment of a Population Health Intervention to Promote Physical Activity after the Winter Holidays

Background: Very few experimental studies exist describing the effect of changes to the built environment and opportunities for physical activity (PA). We examined the impact of an urban trail created on a frozen waterway on visitor counts and PA levels. Methods: We studied a natural experiment in Winnipeg, Manitoba, Canada that included 374,204 and 237,362 trail users during the 2017/2018 and 2018/2019 winter seasons. The intervention was a 10 km frozen waterway trail lasting 8–10 weeks. The comparator conditions were the time periods immediately before and after the intervention when ~10 kms of land-based trails were accessible to the public. A convenience sample of 466 participants provided directly measured PA while on the frozen waterway. Results: Most trail users were 35 years or older (73%), Caucasian (77%), and had an annual household income >$50,000 (61%). Mean daily trail network visits increased ~four-fold when the frozen waterway was open (median and interquartile range (IQR) = 710 (239–1839) vs. 2897 (1360–5583) visits/day, p < 0.001), compared with when it was closed. Users achieved medians of 3852 steps (IQR: 2574–5496 steps) and 23 min (IQR: 13–37 min) of moderate to vigorous intensity PA (MVPA) per visit, while 37% of users achieved ≥30 min of MVPA. Conclusion: A winter-specific urban trail network on a frozen waterway substantially increased visits to an existing urban trail network and was associated with a meaningful dose of MVPA. Walking on water could nudge populations living in cold climates towards more activity during winter months.

Relationships between area-level socioeconomic status and urbanization with active transportation, independent mobility, outdoor time, and physical activity among Canadian children

Background

Active transportation (AT), independent mobility (IM), and outdoor time are promising ways to increase children’s physical activity. However, in order to create interventions to increase those forms of physical activity, it is important to understand the relationships between area-level socioeconomic status (SES) and type of urbanization with AT, IM, outdoor time, and physical activity, and this was the aim of the study.

Methods

One thousand six hundred ninety-nine children in grades 4 to 6 (mean age: 10.2 ± 1.0 years) from three Canadian regions participated. AT, IM, and outdoor time were assessed using questionnaires and physical activity was measured using the SC-StepRX pedometer. Area-level SES was assessed using the median household income of the census tract in which the school was located and type of urbanization was determined for each school using standardized procedures. Generalized linear and general linear mixed models were used to examine the relationships.

Results

Area-level SES and the type of urbanization were generally not related to AT, IM, or physical activity for either gender. However, we observed that both boys and girls living in lower SES areas had decreased odds of spending > 2 h outdoors on weekend days compared to their peers from higher SES areas. Girls living in suburban or rural areas were more likely to spend > 2 h outdoors on weekdays compared to their urban counterparts.

Conclusions

AT, IM, and physical activity are generally not associated with area-level SES or the type of urbanization in this sample of Canadian children. The finding regarding outdoor time showing that both boys and girls of lower SES areas had decreased odds of spending > 2 h outdoors on weekends compared to their peers from higher SES areas suggest that additional efforts should be implemented to offer outdoor play opportunities in lower SES areas.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7420-y) contains supplementary material, which is available to authorized users.

A monitoring system to provide feedback on student physical activity during physical education lessons

School-based physical education (PE) provides opportunities to accumulate moderate-to-vigorous physical activity (MVPA), but many students are insufficiently active during PE lessons. Providing teachers with feedback regarding their students' physical activity may increase the effectiveness of PE for achieving MVPA goals, but existing physical activity monitoring technologies have limitations in class environments. Therefore, the purpose of this study was to develop and validate a system capable of providing feedback on PE lesson MVPA. Equations for translating step counts to %MVPA were derived from measures in 492 students who concurrently wore an ActiGraph GT3X+ (ActiGraph) and Yamax pedometer (Yamax) during a PE lesson. To enhance feedback availability during PE lessons, we then developed a bespoke monitoring system using wireless tri-axial pedometers (HMM) and a smart device app. After developing and testing the monitoring system, we assessed its validity and reliability in 100 students during a PE lesson. There was a strong correlation of 0.896 between step counts and accelerometer-determined %MVPA and quantile regression equations showed good validity for translating step counts to %MVPA with a mean absolute difference of 5.3 (95% CI, 4.4-6.2). The physical activity monitoring system was effective at providing %MVPA during PE lessons with a mean difference of 1.6 ± 7.1 compared with accelerometer-determined %MVPA (7% difference between the two measurement methods). Teachers and students can use a smart device app and wireless pedometers to conveniently obtain feedback during PE lessons. Future studies should determine whether such technologies help teachers to increase physical activity during PE lessons.

The Impact of Exercise Intensity Feedback Using Technology for Children During Active Play: Pilot Study

BACKGROUND

Most children do not engage in enough exercise at the recommended intensity. Using technological devices may increase the time children spend at greater intensities while exercising.

OBJECTIVE

This study aimed to determine if children who are receiving instant feedback on their exercise intensity using technology would spend more time in moderate-vigorous intensity (≥70% of maximum capacity) during active play sessions. It also aimed to explore if the children's physical characteristics were associated with the average percentage of maximal heart rate (HR) reached during sessions.

METHODS

Participants were asked to wear a HR monitor, attached around their chest, for 4 sessions out of the 15 sessions offered. Twenty children aged 5 to 11 years received feedback for 2 random sessions. When receiving feedback, color-coded intensity based on HR was projected onto a wall. Green corresponded to moderate intensity (≥70% of max HR) and red corresponded to a HR below moderate intensity. Age, anthropometric measures, muscle strength, body composition, physical activity level, and fitness level were measured.

RESULTS

The average percentage of maximal HR during a session was similar whether feedback was provided (70.7%, SD 6.4%) or not (71.1%, SD 4.1%) with P=.93. No personal characteristics were associated with the average intensity recorded during the exercise sessions.

CONCLUSIONS

Receiving instant exercise intensity feedback is not associated with a higher proportion of time spent at moderate intensity or above in children aged 5 to 11 years when involved in an active play program. Personal characteristics are not associated with the intensity recorded when participating in an active play program.

Cardiorespiratory fitness is associated with physical literacy in a large sample of Canadian children aged 8 to 12 years

BACKGROUND

The associations between cardiorespiratory fitness (CRF) and physical literacy in children are largely unknown. The aim of this study was to assess the relationships between CRF, measured using the 20-m shuttle run test (20mSRT), and components of physical literacy among Canadian children aged 8-12 years.

METHODS

A total of 9393 (49.9% girls) children, with a mean (SD) age of 10.1 (±1.2) years, from a cross-sectional surveillance study were included for this analysis. The SRT was evaluated using a standardized 15 m or 20 m protocol. All 15 m SRTs were converted to 20mSRT values using a standardized formula. The four domains of physical literacy (Physical Competence, Daily Behaviour, Motivation and Confidence, and Knowledge and Understanding) were measured using the Canadian Assessment of Physical Literacy. Tertiles were identified for 20mSRT laps, representing low, medium, and high CRF for each age and gender group. Cohen's d was used to calculate the effect size between the low and high CRF groups.

RESULTS

CRF was strongly and favourably associated with all components of physical literacy among school-aged Canadian children. The effect size between low and high CRF tertile groups was large for the Physical Competence domain (Cohen's d range: 1.11-1.94) across age and gender groups, followed by moderate to large effect sizes for Motivation and Confidence (Cohen's d range: 0.54-1.18), small to moderate effect sizes for Daily Behaviour (Cohen's d range: 0.25-0.81), and marginal to moderate effect sizes for Knowledge and Understanding (Cohen's d range: 0.08-0.70).

CONCLUSIONS

This study identified strong favourable associations between CRF and physical literacy and its constituent components in children aged 8-12 years. Future research should investigate the sensitivity and specificity of the 20mSRT in screening those with low physical literacy levels.

The relationship between sedentary behaviour and physical literacy in Canadian children: a cross-sectional analysis from the RBC-CAPL Learn to Play study

BACKGROUND

Physical literacy is the foundation of a physically active lifestyle. Sedentary behaviour displays deleterious associations with important health indicators in children. However, the association between sedentary behaviour and physical literacy is unknown. The purpose of this study was to identify the aspects of physical literacy that are associated with key modes of sedentary behaviour among Canadian children participating in the RBC-CAPL Learn to Play study.

METHODS

A total of 8,307 children aged 8.0-12.9 years were included in the present analysis. Physical literacy was assessed using the Canadian Assessment of Physical Literacy, which measures four domains (Physical Competence, Daily Behaviour, Motivation and Confidence, Knowledge and Understanding). Screen-based sedentary behaviours (TV viewing, computer and video game use), non-screen sedentary behaviours (reading, doing homework, sitting and talking to friends, drawing, etc.) and total sedentary behaviour were assessed via self-report questionnaire. Linear regression models were used to determine significant (p<0.05) correlates of each mode of sedentary behaviour.

RESULTS

In comparison to girls, boys reported more screen time (2.7±2.0 vs 2.2±1.8 hours/day, Cohen's d=0.29), and total sedentary behaviour (4.3±2.6 vs 3.9±2.4 hours/day, Cohen's d=0.19), but lower non-screen-based sedentary behaviour (1.6±1.3 vs 1.7±1.3 hours/day, Cohen's d=0.08) (all p< 0.05). Physical Competence (standardized β's: -0.100 to -0.036, all p<0.05) and Motivation and Confidence (standardized β's: -0.274 to -0.083, all p<0.05) were negatively associated with all modes of sedentary behaviour in fully adjusted models. Knowledge and Understanding was negatively associated with screen-based modes of sedentary behaviour (standardized β's: -0.039 to -0.032, all p<0.05), and positively associated with non-screen sedentary behaviour (standardized β: 0.098, p<0.05). Progressive Aerobic Cardiovascular Endurance Run score and log-transformed plank score were negatively associated with all screen-based modes of sedentary behaviour, while the Canadian Agility and Movement Skill Assessment score was negatively associated with all modes of sedentary behaviour other than TV viewing (all p<0.05).

CONCLUSIONS

These results highlight differences in the ways that screen and non-screen sedentary behaviours relate to physical literacy. Public health interventions should continue to target screen-based sedentary behaviours, given their potentially harmful associations with important aspects of physical literacy.

Medical-Grade Physical Activity Monitoring for Measuring Step Count and Moderate-to-Vigorous Physical Activity: Validity and Reliability Study

Background

The use of physical activity (PA) monitors is commonly associated with an increase in habitual PA level in healthy and clinical populations. The PiezoRx is a medical-grade PA monitor that uses adjustable step rate thresholds to estimate moderate-to-vigorous physical activity (MVPA) and is a valid indicator of free-living PA in adults. Laboratory validation of step count derived MVPA in adults is needed to justify the use of these monitors in clinical practice to track individuals’ progress toward meeting PA guidelines that are based on MVPA, not steps.

Objective

The objective of our study was to assess the validity and interinstrument reliability of the PiezoRx to derive step count and MVPA in a laboratory setting compared with criterion measures and other frequently used PA monitors in a diverse sample of adults.

Methods

The adult participants (n=43; 39.4 years, SD 15.2) wore an Omron HJ-320 pedometer, an ActiGraph GT3X accelerometer, and four PiezoRx monitors during a progressive treadmill protocol conducted for 6 minutes at speeds of 2.4, 3.2, 4.0, 5.6, 6.4, and 7.2 km/hour, respectively. The four PiezoRx monitors were set at different MVPA step rate thresholds (MPA in steps/minute/VPA in steps/minute) 100/120, 110/130, height adjusted, and height+fitness adjusted.

Results

The PiezoRx was more correlated (intraclass correlation, ICC=.97; P<.001) to manual step counting than the ActiGraph (ICC=.72; P<.001) and Omron (ICC=.62; P<.001). The PiezoRxs absolute percent error in measuring steps was 2.2% (ActiGraph=15.9%; Omron=15.0%). Compared with indirect calorimetry, the height-adjusted PiezoRx and ActiGraph were accurate measures of the time spent in MVPA (both ICC=.76; P<.001).

Conclusions

The PiezoRx PA monitor appears to be a valid and reliable measure of step count and MVPA in this diverse sample of adults. The device’s ability to measure MVPA may be improved when anthropometric differences are considered, performing at par or better than a research grade accelerometer.

Comparison of Accelerometer-Based Cut-Points for Children's Physical Activity: Counts vs. Steps

Background: Accelerometers measure complex movements of children’s free play moderate-vigorous physical activity (MVPA), including step and non-step movements. Current accelerometer technology has introduced algorithms to measure steps, along with counts. Precise interpretation of accelerometer-based cadence (steps/min) cut-points is necessary for accurately measuring and tracking children’s MVPA. The purpose of this study was to assess the relationships and agreement between accelerometer-based cut-points (cadence and counts/min) to estimate children’s MVPA compared to measured values. Methods: Forty children (8–12 years; 25 boys) played 6–10 games while wearing a portable metabolic analyzer and GT3X⁺ to measure and estimate MVPA, respectively. Correlation, kappa, sensitivity, and specificity assessed the relationships and agreement between measured and estimated MVPA. Results: Games elicited, on average, 6.3 ± 1.6 METs, 64.5 ± 24.7 steps/min, and 3318 ± 1262 vertical (V) and 5350 ± 1547 vector-magnitude (VM) counts/min. The relationship between measured and estimated MVPA intensity was higher for cadence (r = 0.50) than V and VM counts/min (r = 0.38 for both). Agreement using V and VM counts/min for measuring PA intensity varied by cut-points (range: 6.8% (κ = −0.02) to 97.6% (κ = 0.49)), while agreement was low using cadence cut-points (range: 4.0% (κ = 0.0009) to 11.3% (κ = 0.001)). Conclusion: While measured and estimated values were well correlated, using cadence tended to misclassify children’s free-play MVPA.

Validation of PiezoRx Pedometer Derived Sedentary Time

Although pedometers are valid tools for measuring physical activity, to date they have not been used to assess sedentary time. The primary purpose of this study was to determine if the PiezoRx pedometer is a valid and reliable measure of sedentary time compared to the hip-worn Actical accelerometer. A secondary purpose was to compare sedentary time derived via the Fitbit Flex with that of the Actical. Finally, a third purpose was to compare sedentary time derived from the above devices, with that of the ActivPAL inclinometer. Thirty-five participants ages 11-69 years (M_age= 23.3; 21 Female) wore five devices for up to one week: two PiezoRx pedometers, an Actical, an ActivPAL and a Fitbit Flex. Participants recorded daily wear-time of each device using a log sheet. The average sedentary time calculated from the PiezoRx (716±137.68 min/day) was not different from the Actical (694 ±136.11 min/day, p>0.05), although it was higher than the ActivPAL (475±171.52 min/day) and Fitbit Flex (530±149.94 min/day, all p<0.001). Sedentary time from all devices were significantly correlated with each other, with the strongest relationship seen between the Actical and PiezoRx (R²=0.93, p<0.001). In comparison to the ActivPAL, error in PiezoRx- (R²=0.96), Actical- (R²=0.96) and Fitbit Flex- (R²=0.34) determined sedentary time was strongly associated with standing time (all p<0.001). Sedentary time derived using the PiezoRx pedometer may be statistically equivalent to the Actical accelerometer, but not the ActivPAL inclinometer or Fitbit Flex.

Using open source accelerometer analysis to assess physical activity and sedentary behaviour in overweight and obese adults

Background

Physical activity and sedentary behaviour are difficult to assess in overweight and obese adults. However, the use of open-source, raw accelerometer data analysis could overcome this. This study compared raw accelerometer and questionnaire-assessed moderate-to-vigorous physical activity (MVPA), walking and sedentary behaviour in normal, overweight and obese adults, and determined the effect of using different methods to categorise overweight and obesity, namely body mass index (BMI), bioelectrical impedance analysis (BIA) and waist-to-hip ratio (WHR).

Methods

One hundred twenty adults, aged 24–60 years, wore a raw, tri-axial accelerometer (Actigraph GT3X+), for 3 days and completed a physical activity questionnaire (IPAQ-S). We used open-source accelerometer analyses to estimate MVPA, walking and sedentary behaviour from a single raw accelerometer signal. Accelerometer and questionnaire-assessed measures were compared in normal, overweight and obese adults categorised using BMI, BIA and WHR.

Results

Relationships between accelerometer and questionnaire-assessed MVPA (Rs = 0.30 to 0.48) and walking (Rs = 0.43 to 0.58) were stronger in normal and overweight groups whilst sedentary behaviour were modest (Rs = 0.22 to 0.38) in normal, overweight and obese groups. The use of WHR resulted in stronger agreement between the questionnaire and accelerometer than BMI and BIA. Finally, accelerometer data showed stronger associations with BMI, BIA and WHR (Rs = 0.40 to 0.77) than questionnaire data (Rs = 0.24 to 0.37).

Conclusions

Open-source, raw accelerometer data analysis can be used to estimate MVPA, walking and sedentary behaviour from a single acceleration signal in normal, overweight and obese adults. Our data supports the use of WHR to categorise overweight and obese adults. This evidence helps researchers obtain more accurate measures of physical activity and sedentary behaviour in overweight and obese populations.

Validation of the PiezoRx® Step Count and Moderate to Vigorous Physical Activity Times in Free Living Conditions in Adults: A Pilot Study

The purpose of the study was to: 1) Validate the PiezoRx® for steps and intensity related physical activity in free-living conditions compared to the criterion measure. 2) Compare PiezoRx®'s steps and intensity related physical activity to physiological assessments. 3) To assess the utility of the PiezoRx® in a subsample of participants. Thirty-nine participants consisting of 28 females aged 54.9±10.6 (33-74) years and 11 males aged 63.9±10.9 (44-80) years wore the PiezoRx® physical activity monitor and the ActiGraph® accelerometer for one full week and completed a physical assessment. A subsample (n=24) wore the PiezoRx® for an additional two weeks and completed a questionnaire regarding usability. The PiezoRx® had strong correlations to the ActiGraph® for step count (r=0.88; p<0.001), moderate-vigorous physical activity (MVPA) (r=0.70; p<0.001), and sedentary activity (r=0.93; p<0.001) in the 1-week monitoring period. The PiezoRx®'s steps/day and MVPA/week were negatively correlated (p<0.001) to body mass index and waist circumference, and positively correlated (p<0.05) to aerobic fitness, pushups, and 30 second sit-to-stand. Within the subsample who completed the additional two-week monitoring, 75% of participants reported that the PiezoRx® increased their physical activity. In conclusion, The PiezoRx® appears to be a valid measure of free-living PA compared to accelerometry. Because of the correlations of the PiezoRx®'s steps/day and MVPA/week to anthropometric, musculoskeletal and aerobic fitness these PA measures may be valuable objective surrogates to use in clinical or professional practice for physical health.

Examining Incentives to Promote Physical Activity Maintenance Among Hospital Employees Not Achieving 10,000 Daily Steps: A Web-Based Randomized Controlled Trial Protocol

BACKGROUND

The economic burden of physical inactivity in Canada is estimated at Can $6.8 billion (US $5 billion) per year. Employers bear a substantial proportion of the economic costs, as they pay more for inactive workers in health care and other organizational costs. In response, many Canadian employers offer wellness programs, though these are often underutilized. While financial health incentives have been proposed as one way of increasing participation, their longer term effects (ie postintervention effects) are not clear.

OBJECTIVE

The objective of this paper is to outline the methodology for a randomized control trial (RCT) examining the longer term impact of an existing physical activity promotion program that is enhanced by adding guaranteed rewards (Can $1 [US $0.74] per day step goal met) in a lower active hospital employee population (less than 10,000 steps per day).

METHODS

A 12-week, parallel-arm RCT (with a 12-week postintervention follow-up) will be employed. Employees using Change4Life (a fully automated, incentive-based wellness program) and accumulating fewer than 10,000 steps per day at baseline (weeks 1 to 2) will be randomly allocated (1:1) to standard care (wellness program, accelerometer) or an intervention group (standard care plus guaranteed incentives). All study participants will be asked to wear the accelerometer and synchronize it to Change4Life daily, although only intervention group participants will receive guaranteed incentives for reaching tailored daily step count goals (Can $1 [US $0.74] per day; weeks 3 to 12). The primary study outcome will be mean proportion of participant-days step goal reached during the postintervention follow-up period (week 24). Mean proportion of participant-days step goal reached during the intervention period (week 12) will be a secondary outcome.

RESULTS

Enrollment for the study will be completed in February 2017. Data analysis will commence in September 2017. Study results are to be published in the winter of 2018.

CONCLUSIONS

This protocol was designed to examine the impact of guaranteed rewards on physical activity maintenance in lower active hospital employees.

CLINICALTRIAL

ClinicalTrials.gov NCT02638675; https://clinicaltrials.gov/ct2/show/NCT0 2638675 (Archived by WebCite at http://www.webcitation.org/6g4pvZvhW).

Comparison of ActiGraph GT3X+ and Actical accelerometer data in 9-11-year-old Canadian children

Accelerometry is the gold standard for field-based physical activity assessment in children; however, the plethora of devices, data reduction procedures, and cut-points available limits comparability between studies. This study aimed to compare physical activity variables from the ActiGraph GT3X+ and Actical accelerometers in children under free-living conditions. A cross-sectional study of 379 children aged 9-11 years from Ottawa (Canada) was conducted. Children wore the ActiGraph GT3X+ and Actical accelerometers on the hip simultaneously for 7 consecutive days (24-h protocol). Moderate-to-vigorous (MVPA), vigorous (VPA), moderate (MPA), and light (LPA) physical activity, as well as sedentary time, (SED) were derived using established data reduction protocols. Excellent agreement between devices was observed for MVPA (ICC = 0.73-0.80), with fair to good agreement for MPA, LPA and SED, and poor agreement for VPA. Bland-Altman plots showed excellent agreement for MVPA, LPA, and SED, adequate agreement for MPA, and poor agreement for VPA. MVPA derived from the Actical was 11.7% lower than the ActiGraph GT3X+. The ActiGraph GT3X+ and Actical are comparable for measuring children's MVPA. However, comparison between devices for VPA, MPA, LPA, and SED are highly dependent on data reduction procedures and cut-points, and should be interpreted with caution.

Validation of Fitbit-Flex as a measure of free-living physical activity in a community-based phase III cardiac rehabilitation population

BACKGROUND

Accurate physical activity monitoring is important for cardiac patients. Novel activity monitoring devices may enable precise measurement of physical activity. This study aimed to validate Fitbit-Flex against Actigraph accelerometer for monitoring physical activity.

DESIGN

A validation study with a comparative design.

METHODS

Cardiac patients and family members participating in community-based exercise programs wore Fitbit-Flex and Actigraph simultaneously over four days to monitor daily step counts and minutes of moderate to vigorous physical activity (MVPA).

RESULTS

Participants (N = 48) comprised 52.1% males, with a mean age of 65.6 ± 6.9 years and 58.9% had a cardiac diagnosis. Fitbit-Flex and Actigraph were significantly correlated in males, females, total participants and cardiac patients for step counts (r = .96; r = .95; r = .95; r = .95), though less so for MVPA (r = .81; r = .65, r = .74; r = .71). As step counts increased the differences between Fitbit-Flex and Actigraph also increased. Fitbit-Flex over-estimated step counts in females (556 steps/day), males (1462 steps/day) and total participants (1038 steps/day) as well as for minutes of MVPA in females (4 min/day), males (15 min/day) and total participants (10 min/day). Fitbit-Flex had high sensitivity and specificity in classifying participants who achieved the recommended physical activity guidelines.

CONCLUSION

Fitbit-Flex is accurate in assessing attainment of physical activity guideline recommendations and is useful for monitoring physical activity in cardiac patients. The device does, however, slightly over-estimate step counts and MVPA.