The geospatial and conceptual configuration of the natural environment impacts the association with health outcomes and behavior in children and adolescents.

BACKGROUND: Studies investigating associations between natural environments and health outcomes or health behaviors in children and adolescents yielded heterogenous results to date. This may be the result of different geospatial configurations of the natural environment and confounding characteristics of the study population. Thus, we investigated how the relationship between the natural environment and mental health, muscular fitness, and physical activity varies depending on the geospatial configuration of nature and children's and adolescents' characteristics. METHODS: Data were derived from the German Motorik-Modul (MoMo) cohort study (2018-2020) that investigates physical activity, muscular fitness, and health parameters in a national sample of children and adolescents (N = 2843) between four and 17 years (Mage = 10.46 ± 3.49 years; 48.3% girls). Mental health was assessed via questionnaire, muscular fitness via standing long jump, and physical activity with 7-day accelerometer measurement. Using geographic information systems, land cover, and land use data, three different nature definitions were applied. Both circular buffers (100-1000 m) and street-network buffers (1000-5000 m) were created for each of the nature definitions. Associations were explored with linear regression models, and interaction analysis was used to investigate how those relationships vary by gender, age, and socio-economic status. RESULTS: The relationship between the three outcomes and the natural environment varied considerably depending on the nature definition, buffer size, and buffer type, as well as socio-demographic characteristics. Specifically, when comparing youth with a high socio-economic status to those with a medium socio-economic status, smaller circular buffer distances were related to less physical activity, but larger street-network buffer distances were related to greater mental health problems. Distinct relationships also occurred for youth with low socio-economic status in those relationships, with the pattern being less clear. CONCLUSIONS: For future health research studies that investigate the role of the natural environment, we argue for the development of an a-priori model that integrates both geospatial considerations (nature definition, buffer type, and buffer size) and conceptual considerations (health outcome/behavior, sample characteristics) based on potentially underlying mechanisms that link the natural environment and the health outcome or behavior under investigation to theoretically underpin the geospatial configuration of the natural environment.

The relationship of self-reported and device-based measures of physical activity and health-related quality of life in adolescents.

BACKGROUND: Physical activity (PA) has beneficial effects on health and health-related quality of life (HRQoL), which is a protective factor of illness and mortality. The purpose of this examination was to investigate if self-reported and device-based measures of PA were related to HRQoL in adolescents. METHODS: Participants (N = 1565; 54.3% female; Mage = 14.37 years, SDage = 1.99) were recruited from 167 sample points across Germany. Adolescents self-reported their PA, supplemented by a 1-week examination of device-based PA using accelerometry. Additionally, they completed the multidimensional KIDSCREEN-27 to assess HRQoL. RESULTS: Results showed that self-reported PA was correlated with overall HRQoL, Physical Well-Being, Psychological Well-Being, Social Support & Peers, and School Environment, whereas device-based PA was only correlated with Physical as well as Psychological Well-Being. Further, self-reported PA significantly predicted all facets of HRQoL except for Autonomy and Parent Relations, whereas device-based PA solely heightened the amount of explained variance in the Physical Well-Being subscale. CONCLUSIONS: Findings demonstrate the importance of self-reported PA as it is related to almost all facets of HRQoL. Both measures of PA are not congruent in their relationship with HRQoL and thus implications have to be carefully considered. Future studies should investigate the direct effect of PA on HRQoL and health in a longitudinal approach to account for the causality of effects.

Comparison of self-reported & device-based, measured physical activity among children in Germany.

BACKGROUND: As children show a more complex but less structured movement behavior than adults, assessment of their many spontaneous and impulsive movements is a challenge for physical activity (PA) assessment. Since neither questionnaires nor accelerometers enable optimal detection of all facets of PA, a multimodal, combined approach of self-reported and device-based methods is recommended. Based on the number of days on which the participants reached the physical activity (PA) values given in the WHO guideline, this study examines 1) the difference between self-reported and device-based, measured PA and 2) whether PA differences between age and gender groups obtained by two methods are comparable. METHODS: Participants aged 6-17 years were randomly chosen and data were collected representatively at 167 sample points throughout Germany within the Motorik-Modul Study. PA of n = 2694 participants (52.3% female) was measured using the ActiGraph accelerometer (ACC) and a physical activity questionnaire (PAQ). The sample was divided into three age groups (6-10 yrs. n = 788, 11-13 yrs. n = 823, 14-17 yrs. n = 1083). Numbers of days per week with at least 60 min moderate to vigorous PA (MVPA) were analyzed for both methods. RESULTS: Only every 25th respondent (4%) reaches the WHO standard of 60 min MVPA every day if measured with ACC. Self-reported PA was slightly higher (9%) (meanPAQ = 3.82 days; meanACC = 2.34 days; Fmethod = 915.85; p = <.001; fCohen = .64). The differences between the methods are significantly smaller in younger children than in the older age groups (Fage = 264.2, p < .001; fCohen = .48). The older the subjects are, the lower is the proportion of those who meet the WHO guideline on each day, with girls meeting the guideline less frequently than boys in all age groups. CONCLUSION: Children and adolescents living in Germany show a very low adherence to the WHO guideline on PA. While younger children are much more active with their free play, especially children over 10 years of age and especially girls should be the target of programs to increase PA.

Comparison of Self-Reported and Device-Based Measured Physical Activity Using Measures of Stability, Reliability, and Validity in Adults and Children.

Quantification of physical activity (PA) depends on the type of measurement and analysis method making it difficult to compare adherence to PA guidelines. Therefore, test-retest reliability, validity, and stability for self-reported (i.e., questionnaire and diary) and device-based measured (i.e., accelerometry with 10/60 s epochs) PA was compared in 32 adults and 32 children from the SMARTFAMILY study to examine if differences in these measurement tools are systematic. PA was collected during two separate measurement weeks and the relationship for each quality criteria was analyzed using Spearman correlation. Results showed the highest PA values for questionnaires followed by 10-s and 60-s epochs measured by accelerometers. Levels of PA were lowest when measured by diary. Only accelerometry demonstrated reliable, valid, and stable results for the two measurement weeks, the questionnaire yielded mixed results and the diary showed only a few significant correlations. Overall, higher correlations for the quality criteria were found for moderate than for vigorous PA and the results differed between children and adults. Since the differences were not found to be systematic, the choice of measurement tools should be carefully considered by anyone working with PA outcomes, especially if vigorous PA is the parameter of interest.

Ambulatory Assessment for Physical Activity Research: State of the Science, Best Practices and Future Directions.

Technological and digital progress benefits physical activity (PA) research. Here we compiled expert knowledge on how Ambulatory Assessment (AA) is utilized to advance PA research, i.e., we present results of the 2nd International CAPA Workshop 2019 "Physical Activity Assessment - State of the Science, Best Practices, Future Directions" where invited researchers with experience in PA assessment, evaluation, technology and application participated. First, we provide readers with the state of the AA science, then we give best practice recommendations on how to measure PA via AA and shed light on methodological frontiers, and we furthermore discuss future directions. AA encompasses a class of methods that allows the study of PA and its behavioral, biological and physiological correlates as they unfold in everyday life. AA includes monitoring of movement (e.g., via accelerometry), physiological function (e.g., via mobile electrocardiogram), contextual information (e.g., via geolocation-tracking), and ecological momentary assessment (EMA; e.g., electronic diaries) to capture self-reported information. The strengths of AA are data assessment that near realtime, which minimizes retrospective biases in real-world settings, consequentially enabling ecological valid findings. Importantly, AA enables multiple assessments across time within subjects resulting in intensive longitudinal data (ILD), which allows unraveling within-person determinants of PA in everyday life. In this paper, we show how AA methods such as triggered e-diaries and geolocation-tracking can be used to measure PA and its correlates, and furthermore how these findings may translate into real-life interventions. In sum, AA provides numerous possibilities for PA research, especially the opportunity to tackle within- subject antecedents, concomitants, and consequences of PA as they unfold in everyday life. In-depth insights on determinants of PA could help us design and deliver impactful interventions in real-world contexts, thus enabling us to solve critical health issues in the 21st century such as insufficient PA and high levels of sedentary behavior.

The Challenge of Incomplete Data in Accelerometer Studies: Characteristics of Nonparticipation and Noncompliance in a Nationwide Sample of Adolescents and Young Adults in Germany.

BACKGROUND: Incomplete data due to nonparticipation and noncompliance with the study protocol can bias the results of studies. We investigated how a nationwide accelerometer sample of adolescents and young adults is affected by such incomplete data. METHODS: We analyzed cross-sectional data from 6465 participants (11-31 y old) who participated in a national health survey in Germany (KiGGS Wave 2; 2014-2017). The data included information about the participation in the measurement of physical activity using accelerometers, compliance with the wear-time protocol, and sociodemographic and health-related variables. Multivariable regression analyses were conducted to detect factors associated with incomplete data. RESULTS: Of the total sample, 78.0% participated in the accelerometer part of the study, and 83.5% of the participants with data available complied with the wear-time protocol. In 11- to 17-year-olds, the likelihood of having incomplete accelerometer data was higher in boys, older adolescents, adolescents with a lower sociodemographic status, adolescents with overweight, adolescents not participating in organized sport, adolescents not speaking only German at home, current smokers, and adolescents having a higher soft drink consumption. In 18- to 31-year-olds, the likelihood of having incomplete accelerometer data was higher in men, adults with a lower educational level, adults not speaking only German at home, and adults who smoke. CONCLUSIONS: Our results suggest that accelerometer samples are biased such that participants with more beneficial health behaviors provide complete accelerometer data more often. This knowledge should be used to design effective recruitment strategies and should be considered when interpreting results of accelerometer studies.

Active school transport routines during school transitions: Socio-structural predictors of changes from childhood into early adulthood.

The purpose of this study is to investigate socio-structural predictors of active school transport (AST) change and to explore the stability and changes of transport modes during school transitions and into early adulthood in Germany. School transport mode, urbanicity level, socioeconomic status, and migration background were assessed in 624 children (8.9 ± 1.1 years, 51% female) and 444 adolescents (14.9 ± 1.7 years, 48% female) which were followed up longitudinally six years later. The results of multinomial logistic regressions and transition probability calculations indicated that residing outside of rural areas at baseline and follow-up predicts retaining or switching to AST in adolescence. Similarly, higher socioeconomic status at baseline predicted retaining or switching to AST in early adulthood. This research suggests that transition periods are crucial understanding AST behavior and may provide new opportunities for tailored AST promotion programs for different age groups.

Physical activity in 9-15 year-old pediatric cancer survivors compared to a nationwide sample.

INTRODUCTION: Sufficient physical activity (PA) has the potential to mitigate late effects of cancer, but objective data of PA levels in adolescents are scarce. The aim of this study was to investigate differences in PA behavior between childhood cancer survivors (CCS) and healthy peers. METHODS: PA levels of n = 74 CCS and n = 1304 healthy peers from the MoMo study aged 9-15 years were assessed with validated objective accelerometry and group means were compared. A binary multiple logistic regression was performed to investigate the potential predictors of PA. RESULTS: CCS spent significantly more time sedentary (p < 0.001) and less time in moderate-to-vigorous physical activity (p = 0.002) compared to the healthy cohort. Subgroup analysis revealed the largest deviations of PA levels for CCS aged 9-11 years who fulfilled international PA recommendations on significantly fewer days than MoMo (p < 0.01). Health conditions seem to be a predictor concerning the fulfillment of international PA recommendations by the WHO (p = 0.015). CONCLUSIONS: Our study identified vulnerable groups which seem to require targeted exercise and health behavior change programs to increase physical activity and reduce sedentary time. The presence of treatment sequelae as a significant predictor of insufficient physical activity underlines the need of multidisciplinary supportive care approaches.

Physical Activity and Recurrent Pain in Children and Adolescents in Germany-Results from the MoMo Study.

Recurrent pain can be a significant disruption in the activities of daily life, and is not only a health problem in adults but also in children and adolescents. This study analyzed the prevalence of recurrent pain in the current sample (n = 1516; 11-17 years (meanage = 14.4 ± 2.0 years); 50.8% female) of a nationwide study in Germany, evaluated the association of participants' device-based physical activity (PA) with the prevalence of recurrent pain, and assessed whether children and adolescents who reported pain for the last three months accumulated less PA than those who did not. A higher prevalence was found in girls for recurrent headaches (42.2% vs. 28.7%), abdominal pain (28.2% vs. 20.1%), and back pain (26.9% vs. 19.5%). We found higher odds for recurrent headaches in girls (OR = 1.54) and in participants that did not reach at least 60 min of moderate to vigorous PA (MVPA) per day (OR = 2.06). Girls who reported recurrent headaches accumulated 4.7 min less MVPA per day than those without. The prevalence of pain remains at a high level in the German youth and underscores the need for interventions to improve the health situations of children and adolescents.

A Study on the Psychometric Properties of the Short Version of the Physical Activity Enjoyment Scale in an Adult Population.

A new measure of the short form of the Physical Activity Enjoyment Scale (PACES-S), including four items, has been developed that focuses on the subjective experience of enjoyment. As validation has so far only been conducted in a youth population, the purpose of the present article was to test the psychometric properties of the measure in an adult population in three studies. In the first study (n = 1017) the results supported the unidimensional structure of the instrument (χ2 = 10.0; df = 2; p < 0.01; CFI = 0.992; RMSEA = 0.063), revealed a satisfactory level of internal consistency (ω = 0.79), and showed that the measure is invariant across gender. The results on factorial validity and internal consistency were generally supported by the second study (n = 482), which additionally showed satisfactory test-retest reliability (r = 0.73). Finally, the third study (n = 1336) also supported the factorial validity and internal consistency of the measure and additionally showed a positive correlation with physical activity (r = 0.40), thus supporting the criterion-related validity of the measure. This more economical version of PACES seems to be particularly useful for large-scale studies.

Assessment of 24-hour physical behaviour in children and adolescents via wearables: a systematic review of free-living validation studies.

Objectives: Studies that assess all three dimensions of the integrative 24-hour physical behaviour (PB) construct, namely, intensity, posture/activity type and biological state, are on the rise. However, reviews on validation studies that cover intensity, posture/activity type and biological state assessed via wearables are missing. Design: Systematic review. The risk of bias was evaluated by using the QUADAS-2 tool with nine signalling questions separated into four domains (ie, patient selection/study design, index measure, criterion measure, flow and time). Data sources: Peer-reviewed validation studies from electronic databases as well as backward and forward citation searches (1970-July 2021). Eligibility criteria for selecting studies: Wearable validation studies with children and adolescents (age <18 years). Required indicators: (1) study protocol must include real-life conditions; (2) validated device outcome must belong to one dimension of the 24-hour PB construct; (3) the study protocol must include a criterion measure; (4) study results must be published in peer-reviewed English language journals. Results: Out of 13 285 unique search results, 76 articles with 51 different wearables were included and reviewed. Most studies (68.4%) validated an intensity measure outcome such as energy expenditure, but only 15.9% of studies validated biological state outcomes, while 15.8% of studies validated posture/activity type outcomes. We identified six wearables that had been used to validate outcomes from two different dimensions and only two wearables (ie, ActiGraph GT1M and ActiGraph GT3X+) that validated outcomes from all three dimensions. The percentage of studies meeting a given quality criterion ranged from 44.7% to 92.1%. Only 18 studies were classified as 'low risk' or 'some concerns'. Summary: Validation studies on biological state and posture/activity outcomes are rare in children and adolescents. Most studies did not meet published quality principles. Standardised protocols embedded in a validation framework are needed. PROSPERO registration number: CRD42021230894.

Indicators to Assess Physical Health of Children and Adolescents in Activity Research-A Scoping Review.

Sufficient physical activity can help promote and maintain health, while its lack can jeopardize it. Since health and physical activity lay their foundation for later life in childhood and adolescence, it is important to examine this relationship from the beginning. Therefore, this scoping review aims to provide an overview of physical health indicators in children and adolescents in research on the effects of physical activity and sedentary behavior. We identified the indicators used to quantify or assess physical health and summarized the methods used to measure these indicators. We systematically searched Scopus, Pubmed, and Web of Science databases for systematic reviews. The search yielded 4595 records from which 32 records were included in the review. The measurements for physical health reported in the reviews contained measures of body composition, cardiometabolic biomarkers, physical fitness, harm/injury, or bone health. Body composition was the most used indicator to assess and evaluate physical health in children, whereas information on harm and injury was barely available. In future research longitudinal studies are mandatory to focus on the prospective relationships between physical activity or sedentary behavior, and physical health.

Population density predicts youth's physical activity changes during Covid-19 - Results from the MoMo study.

Children in Germany showed positive physical activity changes during the first Covid-19 lockdown in April 2020, but it is unclear how the changes relate to population density, which we investigated in a longitudinal sample of 1711 youth (4-17 years). For each ten citizens more per km2, less positive physical activity changes were observed. For example, a child living in an area with 100 citizens/km2 increased daily life physical activity by 44.50 min/day, whereas a child living in an area with 3000 citizens/km2 only engaged in an additional 9.70 min/day. Policymakers should ensure that youth in densely populated areas have access to physical activity opportunities during the pandemic.

A Short Version of the Physical Activity Enjoyment Scale: Development and Psychometric Properties.

OBJECTIVE: The purposes of this paper were to (a) develop a new short, theory-driven, version of the physical activity enjoyment scale (PACES-S) using content analysis; and (b) subsequently to measure the psychometric properties (construct validity, internal consistency, test-retest reliability, and concurrent validity) of the PACES-S for adolescents. METHODS: Six experts used a four-point Likert scale to assess the content validity of each of the 16 items of the physical activity enjoyment scale according to a provided definition of physical activity enjoyment. Based on the results, exploratory factor analysis was used to analyze survey data from a longitudinal study of 182 individuals (Measure 1 of Study 1: 15.75 ± 3.39 yrs; 56.6% boys, 43.4% girls), and confirmatory factor analysis (Measure 2 of Study 1: 15.69 ± 3.44 yrs; 56.3% boys, 43.7% girls) was used to analyze the survey data from a cross-sectional study of 3219 individuals (Study 2; 15.99 ± 3.10 yrs; 47.8% boys, 52.2% girls) to assess the construct validity of the new measure. To assess the reliability, test-retest reliability was assessed in Study 1 and internal consistency in Study 1 and 2. For the concurrent validity, correlations with self-reported and device-based physical activity behavior were assessed in both studies. RESULTS: Four out of sixteen items were selected for PACES-S. Exploratory factor analysis and confirmatory factor analyses identified and supported its factorial validity (χ2 = 53.62, df = 2, p < 0.001; RMSEA = 0.073; CFI = 0.99; RFI = 0.96; NFI = 0.99; TLI = 0.96; IFI = 0.99). Results showed good test-retest reliability (r = 0.76) and internal consistency (a = 0.82 to 0.88). Regarding concurrent validity, the results showed positive correlations with a physical activity questionnaire (Study 1: r = 0.36), with a physical activity diary (Study 1: r = 0.44), and with accelerometer-recorded data (Study 1: r = 0.32; Study 2: r = 0.21). CONCLUSIONS: The results indicate that PACES-S is a reliable and valid instrument that may be particularly useful to measure physical activity enjoyment in large-scale studies. It shows comparable measurement properties as the long version of PACES.

Reply to Kersting et al. Comment on "Wunsch et al. The Impact of COVID-19 on the Interrelation of Physical Activity, Screen Time and Health-Related Quality of Life in Children and Adolescents in Germany: Results of the Motorik-Modul Study. Children 2021, 8, 98".

In reply to the comment of Kersting et al [...].

The Impact of COVID-19 on the Interrelation of Physical Activity, Screen Time and Health-Related Quality of Life in Children and Adolescents in Germany: Results of the Motorik-Modul Study.

Reduced physical activity (PA) and prolonged screen time (ST) negatively influence health-related quality of life (HRQoL), a protective factor against illness and mortality. Studies addressing the relationship between PA, ST, and mental health in youth are scarce, especially in times with high mental health burdens like the COVID-19 pandemic. The purpose of this examination was to investigate whether PA, ST, and HRQoL before COVID-19 predict PA, ST, and HRQoL during the COVID-19 pandemic. Participants from the Motorik-Modul Study (MoMo; N = 1711; Mage = 10.36 (SD = 4.04) years, female = 49.8%; healthy weight = 76.8%) self-reported their PA and ST as well as HRQoL both before and during COVID-19. Relationships of all variables, from before to during COVID-19, were investigated through a path prediction model. Results showed all variables during COVID-19 were predicted by the respective levels before COVID-19, independent of gender and age. Cross-lags revealed a negative influence of before COVID-19 ST on during COVID-19 PA. HRQoL before COVID-19 was positively associated with during COVID-19 PA in children younger than 10 years and females, but not in adolescents and boys. As age- and gender-independent negative influence of before COVID-19 ST on during COVID-19 PA has been detected, health policy may be advised to focus on a general reduction in ST instead of PA enhancement to ensure high PA levels.

Measurement of Physical Activity and Sedentary Behavior by Accelerometry Among a Nationwide Sample from the KiGGS and MoMo Study: Study Protocol.

BACKGROUND: Currently, no nationwide objective physical activity data exists for children and adolescents living in Germany. The German Health Interview and Examination Survey for Children and Adolescents (KiGGS) and the Motorik-Modul study (MoMo) is a national cohort study that has incorporated accelerometers in its most recent data collection wave (wave 2, since 2014). This wave 2 marks the first nationwide collection of objective data on the physical activity of children and adolescents living in Germany. OBJECTIVE: The purpose of this protocol is to describe the methods used in the KiGGS and MoMo study to capture the intensity, frequency, and duration of physical activity with accelerometers. METHODS: Participants (N=11,003, aged 6 to 31 years) were instructed to wear an ActiGraph GT3X+ or wGT3X-BT accelerometer laterally on the right hip. Accelerometers were worn on consecutive days during waking hours, including at least 4 valid weekdays and 1 weekend day (wear time >8 hours) in the evaluation. A nonwear time protocol was also implemented. RESULTS: Data collection was completed by October 2017. Data harmonization took place in 2018. The first accelerometer results from this wave were published in 2019, and detailed analyses are ready to be submitted in 2020. CONCLUSIONS: This study protocol provides an overview of technical details and basic choices when using accelerometers in large-scale epidemiological studies. At the same time, the restrictions imposed by the specified filters and the evaluation routines must be taken into account. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/14370.

The physical activity of children and adolescents in Germany 2003-2017: The MoMo-study.

With digitalization and virtual entertainment being the megatrends of the 21st century, there is reasonable concern about the role of physical activity (PA) in the daily life of children and adolescents. To identify risk-groups with insufficient PA and to guide interventions, continuous and representative tracking of PA is crucial. In this paper, representative PA data of children and adolescents from the Motorik-Modul (MoMo) baseline study (2003-2006, N = 4,528) is compared to those of Wave 2 (2014-2017, N = 3,708). Participants aged 4-17 were drawn out of 167 sample points in Germany and the data was weighted to ensure representativeness for Germany. Organized (sports clubs and schools) and unorganized (unorganized sports and playing outside) PA was measured by questionnaire and stratified by sex, age, and socioeconomic status. Contrary to common expectation, overall PA remained stable among youths in the past ten years, however, there is an ongoing trend towards organized forms of PA at the expense of unorganized sports and playing outside. Besides different trends in settings, there is inequality in PA distribution among socioeconomic status and gender, unequally pronounced in different settings.

Physical activity and screen time of children and adolescents before and during the COVID-19 lockdown in Germany: a natural experiment.

The impact of COVID-19 on social life has been drastic and global. However, the different numbers of cases and different actions in different countries have been leading to various interesting yet unexplored effects on human behavior. In the present study, we compare the physical activity and recreational screen time of a representative sample of 1711 4- to 17-year-olds before and during the strictest time of the first COVID-19 lockdown in Germany. We found that sports activity declined whereas recreational screen time increased. However, a substantial increase in habitual physical activities leads to an overall increase in physical activity among children and adolescents in Germany. The effects differ in size but not in their direction between age groups and are stable for boys and girls. We conclude from this natural experiment that physical activity among children and adolescents is highly context-driven and mutual and does not act as a functional opposite to recreational screen time.