Assessing Park Quality with a Wearable Video Device and an Unmanned Aerial System.

Parks are ideal places for promoting physical activity, which is vital for achieving and sustaining good health. Thus, it is important to develop and provide the best methods for assessing aspects of parks that could influence physical activity. This study examined the use of high-tech video capture for describing park quality. Videos were obtained with a wearable video device (WVD) and an unmanned aerial system (UAS) at 28 and 17 parks, respectively. In-person audits of park attributes were performed using the Physical Activity Readiness Assessment (PARA) instrument while video was simultaneously captured. The PARA provides quality ratings of park attributes that range from poor to good. Kappa statistics were calculated to compare in-person PARA outcomes with PARA outcomes obtained by reviewing the WVD and UAS videos. Substantial and almost-perfect agreements were found between WVD and in-person PARAs on the quality of features and amenities and the severity of incivilities. Agreements between UAS and in-person PARAs on feature and amenity quality and incivility severity were unacceptable (mostly fair and moderate). In conclusion, being able to reliably assess park quality using video provides advantages over in-person assessments (e.g., retrospective analysis). In addition, it sets up the possibility of utilizing computer vision to automate the video analysis process.

Direct Observation of COVID-19 Prevention Behaviors and Physical Activity in Public Open Spaces.

Mask wearing and physical distancing are effective at preventing COVID-19 transmission. Little is known about the practice of these behaviors during physical activity (PA). In this longitudinal study, direct observation was used to describe COVID-19 prevention behaviors among physically active individuals. The Viral Transmission Scan (VT-Scan) was used to assess COVID-19 prevention behaviors of people standing, sitting, walking, jogging, and cycling in educational, retail, and residential areas. The VT-Scan was performed once per week over 22 weeks between 11:00 a.m. and 2:30 p.m. Information was manually extracted from videos collected during VT-Scans. A total of 4153 people were described, of which 71.2% were physically active, 80.0% were 18-30 years of age, 14.0% were non-white, 61.0% were female, and were 19.6% obese. Individuals not engaged in PA were less compliant with COVID-19 prevention behaviors than physically active people. Compliance differed by PA type, with walkers less compliant with COVID-19 prevention behaviors than joggers and cyclists. Among those physically active, non-compliance with COVID-19 prevention behaviors was higher in 18-30-year-olds, whites, and men. Engagement in COVID-19 prevention behaviors varies as a function of PA. Efforts to promote compliance with recommendations may benefit from tailored messaging, taking into account PA participation, PA type, and characteristics of physically active individuals.

A comprehensive evaluation of physical activity on sidewalks and streets in three U.S. Cities.

A considerable proportion of outdoor physical activity (PA) is done on sidewalks/streets. The purpose of the current study was to create a comprehensive picture of PA and non-PA (sitting and standing) occurring on sidewalks/streets. A wearable video device was used to capture videos during 2019 in three different size (small, medium, large), U.S. cities along 24 observation routes (sidewalks/streets) located in 24 study areas that varied in walkability, income level, and minority composition. Videos were collected over the course of one year during different times of week and weekend days. Expert reviewers examined each video to extract data on counts of people engaged in different types of activities (e.g., walking) per minute of video. A total of 1154 individuals were described in 1237 min of video as either walking (66.9%), sitting/standing (25.7%), jogging (4.2%), cycling (1.8%) or skating/playing (1.4%). A greater number of active people/min were seen in the evening and in the small city (P < 0.05) while more non-PA people/min were observed in the medium city and during the weekend (P < 0.05). Active and non-PA people/min were associated with walkability, income, and minority composition. For instance, in high walkability, low income areas, 3.2 active people/min were observed in areas with a high percentage of non-minority residents compared to 0.9 active people /min in areas with a high percentage of minority residents. Sidewalks/street activities are related to dynamic interactions between social and physical environmental factors. The results of this study may serve as a reference to which future, similar evaluations can compare.

Multi Agent Architecture for Automated Health Coaching.

For software applications in health coaching domains to be effective, it is vital that they address issues of privacy, modularity, scalability, individualization, data integration, transferability, coordination and flexibility. In this paper, we propose a novel generic multi-agent architecture which serves as a template for health coaching applications involving wearable sensors. Analyzer and communication modules allow different functionalities like goal formation, planning, scheduling, event detection, learning, inter-agent + human communication and long-term data collection, based on the capabilities of the underlying sensor platforms. To show the flexibility of our proposed architecture, we have successfully built two different health coaching systems with the proposed architecture: (1) a static system based on the Fitbit platform where the coaching is done at specific preset times to encourage increased physical activity, and (2) a dynamic system based on the Apple Watch platform where the smart coach adapts and learns when to intervene to encourage physical activity and reduce sedentary behavior.

A Direct Observation Video Method for Describing COVID-19 Transmission Factors on a Micro-Geographical Scale: Viral Transmission (VT)-Scan.

The COVID-19 pandemic severely affected many aspects of human life. While most health agencies agree mask wearing and physical distancing reduce viral transmission, efforts to improve the assessment of these behaviors are lacking. This study aimed to develop a direct observation video method [Viral Transmission (VT)-Scan] for assessing COVID-19 transmission behaviors and related factors (e.g., environmental setting). A wearable video device (WVD) was used to obtain videos of outdoor, public areas. The videos were examined to extract relevant information. All outcomes displayed good to excellent intra- and inter-reliability with intra-class correlation coefficients ranging from 0.836 to 0.997. The majority of people had a mask (60.8%) but 22.1% of them wore it improperly, 45.4% were not physical distancing, and 27.6% were simultaneously mask and physical distancing non-compliant. Transmission behaviors varied by demographics with white, obese males least likely to be mask-compliant and white, obese females least likely to physical distance. Certain environments (e.g., crosswalks) were identified as "hot spots" where higher rates of adverse transmission behaviors occurred. This study introduces a reliable method for obtaining objective data on COVID-19 transmission behaviors and related factors which may be useful for agent-based modeling and policy formation.

Does meeting physical activity recommendations ameliorate association between television viewing with cardiovascular disease risk? A cross-sectional, population-based analysis.

OBJECTIVES: As a common form of sedentary behaviour, television viewing is associated with an increase in body mass index (BMI) as well as overall cardiovascular disease (CVD) risk. This study examined the extent to which meeting the recommended volume of weekly physical activity (PA) reduced the association between television viewing with the outcomes of BMI and CVD risk. A second aim was to determine the number of hours (ie, cut-point) of daily television viewing that conferred a higher BMI and CVD risk for a large population-based sample of adults. DESIGN: Population-based, cross-sectional study. SETTING: UK Biobank recruited across 35 centres in the UK between 2006 and 2010. PRIMARY OUTCOME: CVD risk, as measured by the 30-year Framingham risk score. RESULTS: Linear regression models indicated that every additional hour of television viewing per day was associated with a 3% increase in CVD risk (aCoeff=0.03, d=0.16, p<0.0001); the interaction between television viewing with meeting PA guidelines was marginally associated with CVD risk (aCoeff=0.0010, d=0.01, p=0.014). Each additional hour of television viewing per day was associated with a 0.54 increase in BMI (aCoeff=0.54, d=0.13, p<0.0001); the interaction between television viewing with meeting PA guidelines was not significantly associated with BMI. Regression tree models of the study outcomes revealed that 2.5 hours of television viewing was associated with pronounced increases in BMI and CVD risk. CONCLUSIONS: These data underscore the independent association between television viewing with cardiovascular risk and suggest that reducing television viewing to less than 2.5 hours per day, even in physically active adults, is a clinical and public health priority.

Assessing Physical Activities Occurring on Sidewalks and Streets: Protocol for a Cross-Sectional Study.

BACKGROUND: A considerable proportion of outdoor physical activity (PA) is done on sidewalks and streets, necessitating the development of a reliable measure of PA performed in these settings. The Block Walk Method (BWM) is one of the more common approaches for this purpose. Although it utilizes reliable observation techniques and displays criterion validity, it remains relatively unchanged since its introduction in 2006. It is a nontechnical, labor-intensive, first generation method. Advancing the BWM would contribute significantly to our understanding of PA behavior. OBJECTIVE: This study will develop and test a new BWM that utilizes a wearable video device (WVD) and computer video analysis to assess PAs performed on sidewalks and streets. The specific aims are to improve the BWM by incorporating a WVD (eyeglasses with a high-definition video camera in the frame) into the methodology and advance this WVD-enhanced BWM by applying machine learning and recognition software to automatically extract information on PAs occurring on the sidewalks and streets from the videos. METHODS: Trained observers (1 wearing and 1 not wearing the WVD) will walk together at a set pace along predetermined 1000 ft sidewalk and street observation routes representing low, medium, and high walkable areas. During the walks, the non-WVD observer will use the traditional BWM to record the numbers of individuals standing, sitting, walking, biking, and running in observation fields along the routes. The WVD observer will continuously video the observation fields. Later, 2 investigators will view the videos to determine the number of individuals performing PAs in the observation fields. The video data will then be analyzed automatically using multiple deep convolutional neural networks (CNNs) to determine the number of humans in the observation fields and the type of PAs performed. Bland Altman methods and intraclass correlation coefficients (ICCs) will be used to assess agreement. Potential sources of error such as occlusions (eg, trees) will be assessed using moderator analyses. RESULTS: Outcomes from this study are pending; however, preliminary studies supporting the research protocol indicate that the BWM is reliable for determining the PA mode (Cramer V=.89; P<.001), the address where the PA occurred (Cohen kappa=.85; P<.001), and the number engaged in an observed PA (ICC=.85; P<.001). The number of individuals seen walking along routes was correlated with several environmental characteristics such as sidewalk quality (r=.39; P=.02) and neighborhood aesthetics (r=.49; P<.001). Furthermore, we have used CNNs to detect cars, bikes, and pedestrians as well as individuals using park facilities. CONCLUSIONS: We expect the new approach will enhance measurement accuracy while reducing the burden of data collection. In the future, the capabilities of the WVD-CNN system will be expanded to allow for the determination of other characteristics captured in videos such as caloric expenditure and environmental conditions. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/12976.

Validation of the Block Walk Method for Assessing Physical Activity occurring on Sidewalks/Streets.

The block walk method (BWM) is one of the more common approaches for assessing physical activity (PA) performed on sidewalks/streets; however, it is non-technical, labor-intensive, and lacks validation. This study aimed to validate the BWM and examine the potential for using a wearable video device (WVD) to assess PA occurring on sidewalks/streets. Trained observers (one wearing and one not wearing the WVD) walked together and performed the BWM according to a previously developed protocol along routes in low, medium, and high walkable areas. Two experts then reviewed the videos. A total of 1150 (traditional) and 1087 (video review) individuals were observed during 900 min of observation. When larger numbers of individuals were observed, the traditional method overestimated the overall number of people as well as those walking and sitting/standing, while underestimating the number of runners. Valid estimates of PA occurring on sidewalks/streets can be obtained by the traditional BWM in low and medium walkability areas and/or with non-common activities (cycling); however, its validity is questionable when sidewalks/streets use volume is high. The use of WVDs in PA assessment has the potential to establish new levels of accuracy, reduce resource requirements, and open up the possibility for retrospective analysis.

Steady State Hydration Levels of Career Firefighters in a Large, Population-Based Sample.

OBJECTIVES: To establish the extent of steady state hypohydration among firefighters and examine factors associated with their hydration status. METHODS: Data on 450 career firefighters from 11 randomly selected fire departments had their body composition, total body water (TBW), and hypohydration status assessed using bioelectrical impedance. Measured height and weight were used to determine body mass index (BMI) and weight classification. RESULTS: The hypohydration rate was 17% and 94% of hypohydrated firefighters were obese. A one-unit increase in BMI was associated with an 83% greater likelihood of being hypohydrated. CONCLUSIONS: This study indicates that steady state hypohydration is a significant issue among obese firefighters. Current hydration policies based on previous reports that most (more than 90%) firefighters are hypohydrated in the steady state should be revisited and additional, confirmatory research in this area should be conducted.

Modeling Clinically Validated Physical Activity Assessments Using Commodity Hardware.

Consumer-grade wearable activity devices such as Fitbits are increasingly being used in research settings to promote physical activity (PA) due to their low-cost and widespread popularity. However, Fitbit-derived measures of activity intensity are consistently reported to be less accurate than intensity estimates obtained from research-grade accelerometers (i.e., ActiGraph). As such, the potential for using a Fitbit to measure PA intensity within research contexts remains limited. This study aims to model ActiGraph-based intensity estimates from the validated Freedson vector magnitude (VM3) algorithm using measures of steps, metabolic equivalents, and intensity levels obtained from Fitbit. Minute-level data collected from 19 subjects, who concurrently wore the ActiGraph GT3X and Fitbit Flex devices for an average of 1.8 weeks, were used to generate the model. After testing several modeling methods, a naïve Bayes classifier was chosen based on the lowest achieved error rate. Overall, the model reduced Fitbit to ActiGraph errors from 19.97% to 16.32%. Moreover, the model reduced misclassification of Fitbit-based estimates of moderate-to-vigorous physical activity (MVPA) by 40%, eliminating a statistically significant difference between MVPA estimates derived from ActiGraph and Fitbit. Study findings support the general utility of the model for measuring MVPA with the Fitbit Flex in place of the more costly ActiGraph GT3X accelerometer for young healthy adults.

Physical Activity Assessment Between Consumer- and Research-Grade Accelerometers: A Comparative Study in Free-Living Conditions.

BACKGROUND: Wearable activity monitors such as Fitbit enable users to track various attributes of their physical activity (PA) over time and have the potential to be used in research to promote and measure PA behavior. However, the measurement accuracy of Fitbit in absolute free-living conditions is largely unknown. OBJECTIVE: To examine the measurement congruence between Fitbit Flex and ActiGraph GT3X for quantifying steps, metabolic equivalent tasks (METs), and proportion of time in sedentary activity and light-, moderate-, and vigorous-intensity PA in healthy adults in free-living conditions. METHODS: A convenience sample of 19 participants (4 men and 15 women), aged 18-37 years, concurrently wore the Fitbit Flex (wrist) and ActiGraph GT3X (waist) for 1- or 2-week observation periods (n=3 and n=16, respectively) that included self-reported bouts of daily exercise. Data were examined for daily activity, averaged over 14 days and for minutes of reported exercise. Average day-level data included steps, METs, and proportion of time in different intensity levels. Minute-level data included steps, METs, and mean intensity score (0 = sedentary, 3 = vigorous) for overall reported exercise bouts (N=120) and by exercise type (walking, n=16; run or sports, n=44; cardio machine, n=20). RESULTS: Measures of steps were similar between devices for average day- and minute-level observations (all P values > .05). Fitbit significantly overestimated METs for average daily activity, for overall minutes of reported exercise bouts, and for walking and run or sports exercises (mean difference 0.70, 1.80, 3.16, and 2.00 METs, respectively; all P values < .001). For average daily activity, Fitbit significantly underestimated the proportion of time in sedentary and light intensity by 20% and 34%, respectively, and overestimated time by 3% in both moderate and vigorous intensity (all P values < .001). Mean intensity scores were not different for overall minutes of exercise or for run or sports and cardio-machine exercises (all P values > .05). CONCLUSIONS: Fitbit Flex provides accurate measures of steps for daily activity and minutes of reported exercise, regardless of exercise type. Although the proportion of time in different intensity levels varied between devices, examining the mean intensity score for minute-level bouts across different exercise types enabled interdevice comparisons that revealed similar measures of exercise intensity. Fitbit Flex is shown to have measurement limitations that may affect its potential utility and validity for measuring PA attributes in free-living conditions.

Association of Psychosocial Factors With Physical Activity and Function After Total Knee Replacement: An Exploratory Study.

OBJECTIVES: To examine the association between self-efficacy, social support, and fear of movement with physical activity and function at baseline and after 12 weeks of physical therapy. DESIGN: Nonrandomized cohort study, repeated-measures design. SETTING: Outpatient rehabilitation clinic within the general community. PARTICIPANTS: Adults (N=49) undergoing outpatient physical therapy for total knee replacement (TKR). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Self-efficacy for exercise (SEE), fear of movement, leisure-time physical activity (LTPA), 6-minute walk test (6MWT), and Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) were assessed at baseline and 12 weeks. RESULTS: Mean functional change scores significantly increased at 12 weeks for the 6MWT (95% confidence interval [CI], 42.3-106.2), KOS-ADLS (95% CI, 12.7-23.3), and LTPA (95% CI, 6.5-26.1). Self-efficacy and fear of movement were not significantly associated with function at baseline or 12 weeks. Participants with lower SEE had 6 fewer metabolic equivalents per week of improvement in LTPA than those with high self-efficacy (95% CI, -27.9 to 14.8), and those with high fear of movement had 26.1m less improvement in the 6MWT than those with low fear of movement (95% CI, -42.2 to 94.5). Most participants reported having no family or peer support for exercise. CONCLUSIONS: Physical therapy for TKR improves physical function and self-reported physical activity. High fear of movement and low SEE may be associated with less improvement in physical activity and function over time.

Sustainability of physical activity promoting environments and influences on sustainability following a structural intervention in residential children's homes.

Research examining sustainability of health promotion programs within organizational settings is limited. The Environmental Interventions in Residential Children's Homes (ENRICH) was a structural intervention that trained Wellness Teams (WTs) within residential children's homes (RCH) to target environmental changes that promote physical activity (PA) among residential youth. This study examines the sustainability of PA promoting environments and influences on sustainability within RCHs. A sustainability survey was administered to 14 RCHs 2 years after receiving ENRICH. Variables included sustainability of PA promoting environments, Organizational Influences, perceived organizational and individual benefits, and implementation of PA and general (i.e. Global) wellness activities. Activities reported as sustained and barriers were used descriptively to inform sustainability. Path analyses explained the relationship between sustainability influences and sustainability of PA promoting environments. Sustainability was found in 8 of 14 (57%) RCHs. Sustained activities reflected greater Global versus PA implementation. Global implementation mediated the relationship between Organizational Influences and sustainability, which may have been more easily achieved since Global activities were most likely controlled by WTs and did not require extensive organizational support from RCH administrators. Results highlight the importance of defining and assessing different implementation types when measuring sustainability and influences on sustainability within RCHs organizations.

Food Insecurity Increases the Odds of Obesity Among Young Hispanic Children.

Obesity is a growing public health concern and is more prevalent among low-income and minority populations. Food insecurity may increase the odds of obesity in children. We investigated the association between food insecurity and obesity among low-income, Hispanic, mother-child dyads (n = 74). The United States Department of Agriculture 18-item Household Food Security Survey was used to determine food security status. The majority of households were food insecure (74 %) and one-third (30 %) of children were obese. Food insecurity increased the odds of childhood obesity (OR 10.2; 95 % CI 1.2, 85.5) with stronger associations found within households where mothers were also overweight/obese compared to normal weight (p-for interaction < 0.05). Rates of household food insecurity and childhood obesity were high among this low-income Hispanic sample. Future studies should elucidate the mechanisms through which food insecurity impacts childhood obesity.

Classification tree analysis to examine influences on colorectal cancer screening.

PURPOSE: Identifying correlates of colorectal cancer screening (CRCS) is critical for cancer control and prevention. Classification tree analysis (CTA) is a potentially powerful analytic tool that can identify distinct population subgroups for which CRCS is influenced by any number of multivariable interactions. This study used CTA to identify correlates of CRCS for exclusive population subgroups. METHODS: Data were obtained from the 2007 Health Information National Trends Survey (HINTS) and analyzed in 2014. CTA was employed to determine the association between demographic (n = 11), psychosocial (n = 6), and numeracy (n = 3) variables and CRCS status of adults ≥50 years (n = 3,769). RESULTS: Overall CRCS rate was 66.9 %. Level of doctor avoidance (three categories) was the initial splitting variable, leading to a total of 21 terminal node subgroups of CRCS utilization: (1) avoid doctor, not for fear of illness/death [n = 625 (16.5 %), four subgroups]; (2) avoid doctor, fear illness/death [n = 366 (9.7 %), two subgroups]; (3) do not avoid doctor [n = 2,778 (73.7 %), 15 subgroups]. CONCLUSIONS: Doctor avoidance was an important behavioral influence on CRCS adherence. Use of CTA to identify unique characteristics within population subgroups has merit for tailoring future intervention strategies. Community-based approaches may be effective for reaching individuals who avoid routine doctor visits.

Moderating Effects of Health Literacy on Change in Physical Activity Among Latinas in a Randomized Trial.

INTRODUCTION: Latinas report low rates of physical activity (PA) and are at risk for poor health outcomes. Language and literacy barriers impede access and utilization of PA-related resources. This study examined health literacy as a moderator on changes in moderate-to-vigorous physical activity (MVPA) in 196 Latinas enrolled in Seamos Saludables, a randomized-controlled trial of a 6-month culturally and linguistically adapted PA print intervention METHODS: Secondary analyses were conducted on demographics, acculturation and generation status, and health literacy (Newest Vital Sign). MVPA was determined by 7 day physical activity recall, assessed at baseline and 6 months. General linear models examined interaction effects between health literacy (HL), experimental condition (treatment vs. control), and generation status. RESULTS: Health literacy moderated change in MVPA from baseline to 6 months. The intervention effect was greater among first-generation Latinas with limited health literacy. DISCUSSION: Differences in health literacy level appear to influence MVPA outcomes. Formative research is recommended to ensure that materials are appropriate when developing print-based PA interventions, particularly among first-generation Latinas who are more likely to have limited health literacy.

Effects of a structural intervention and implementation on physical activity among youth in residential children's homes.

This study reports the effects of a structural intervention, ENRICH (Environmental Interventions in Children's Homes) which targeted the physical and social environment within residential children's homes (RCHs) to increase physical activity (PA) among residents (n=799). Participating RCHs (n=29) were randomized to Early (n=17) or Delayed (n=12) groups from 2004 to 2006 and 2006 to 2008, respectively. Children's PA was measured at three time periods (2004, 2006, 2008). Intent-to-treat analysis revealed no intervention impact on PA. Subsequent analyses used process evaluation data to group organizations into high and low PA-promoting RCHs to compare PA level, controlling for assignment to condition. Organizations with high PA-promoting environments were found to have more active youth. Utility of a comprehensive implementation monitoring plan and the need for formative assessment of organizational capacity is discussed.

Health literacy predicts change in physical activity self-efficacy among sedentary Latinas.

Health literacy (HL) is associated with preventive health behaviors. Self-efficacy is a predictor of health behavior, including physical activity (PA); however, causal pathways between HL and self-efficacy for PA are unknown, especially among Latinas who are at risk for chronic disease. To explore this potential relationship, secondary analyses were conducted on data [Shortened Test of Functional Health Literacy in Adults (STOFHLA), PA self-efficacy, and socio-demographics] from a 6-month, randomized controlled trial of a print-based PA intervention (n = 89 Spanish-speaking Latinas). Linear regression models revealed associations between HL and baseline self-efficacy in addition to changes in self-efficacy at 6-months. After controlling for significant covariates, higher HL scores were associated with lower baseline PA self-efficacy. Regardless of treatment assignment, higher HL scores at baseline predicted greater changes in PA self-efficacy at 6-months. HL may contribute to Latinas' improved PA self-efficacy, though further research is warranted.

Randomized controlled trial testing an internet physical activity intervention for sedentary adults.

OBJECTIVE: Internet-based physical activity (PA) interventions have shown promise, although findings remain equivocal. We used formative research to enhance a previously demonstrated program (Step into Motion) with the goal of developing an Internet program poised for dissemination. METHODS: We conducted focus groups to identify Internet features targeted to theoretical constructs (social cognitive theory) predictive of PA behavior and rated as "useful for increasing PA." We identified 5 theory-targeted Internet features as useful for increasing PA: (1) a PA tracking/logging calendar targeting self-monitoring and goal setting; (2) geographic mapping tools targeting perceived environment; (3) a discussion forum targeting social support; (4) exercise videos targeting observational learning; and (5) regular updates of peer PA progress targeting situation. We then tested the efficacy of the enhanced program (enhanced Internet, EI; N = 25) in relation to publicly available PA Websites (standard Internet, SI; N = 28) among 53 participants in a randomized controlled trial. RESULTS: The EI arm increased PA in relation to the SI arm at 3 months (18.4 to 186.0 min/wk vs. 20.9 to 57.3 min/wk; p = .03) but between-groups differences were not observed at 6 months (176.8 vs. 133.5 min/wk; p = .44). EI participants maintained PA from 3 to 6 months (186.0 to 176.8 min/wk), and the SI group increased PA (57.3 to 133.5 min/wk). CONCLUSION: The EI program was efficacious at improving PA levels in relation to publicly available Websites initially, but differences in PA levels were not maintained at 6 months. Future research should identify Internet features that promote long-term maintenance.