Long-term effects of daily physical education throughout compulsory school on duration of physical activity in young adulthood: an 11-year prospective controlled study

Progress and Challenges in Measles and Rubella Elimination in the WHO European Region

The elimination of both measles and rubella remains a priority for all 53 Member States of the World Health Organization (WHO) European Region. To provide an update on the epidemiological status of measles and rubella in the Region, we reviewed surveillance data on both diseases for 2023 submitted monthly by national surveillance institutions. We analyzed the cases of measles and rubella for 2023 by age group, case classification, vaccination, hospitalization, and importation status and report on measles-related deaths. In 2023, 60,860 measles cases, including 13 fatal cases, were reported in 41 countries. Most cases (95%; n = 57,584) were reported by six countries: Azerbaijan, Kazakhstan, Kyrgyzstan, Romania, the Russian Federation, and Türkiye. Of the 60,848 cases with data on age, 19,137 (31%) were 1-4 years old and 12,838 (21%) were 5-9 years old. A total of 10,412 (17%) were 20 years and older. The genotypes identified in the Region were largely dominated by D8 variants (n = 1357) and the remainder were B3 variants (n = 221). In 2023, 345 rubella cases were reported by 17 countries, mostly from Poland, Kyrgyzstan, Tajikistan, Türkiye, and Ukraine. A total of 262 cases (76%) were classified as clinically compatible and 79 (23%) were laboratory-confirmed. To achieve the elimination of measles and rubella in the Region, political commitment needs to be revived to enable urgent efforts to increase vaccination coverage, improve surveillance and outbreak preparedness, and respond immediately to outbreaks.

Adaptation of a Danish online version of the Oxford Physical Activity Questionnaire (OPAQ) for secondary school students—a pilot study

Objective

To adapt and partly validate a Danish online version of the patient-reported outcome measure (PROM) Oxford Physical Activity Questionnaire (“OPAQ”) and evaluate mobile phones and tablets as data capturing tool to identify potential problems and deficiencies in the PROM prior to implementation in the full study.

Methods

The OPAQ was translated into Danish by a formalised forward-backward translation procedure. Face validity was examined by interviewing 12 school students aged 10–15, recruited from two Danish public schools. After modifications, the online version of the Danish OPAQ was pilot tested in a convenience sample of seven school students for 1 week. Simultaneous objective accelerometer data were captured during the registration period.

Results

No major challenges were identified when translating OPAQ. Based on the interviews, the Danish version of OPAQ was perceived to be easy to understand in general, and the questions were relevant for tracking activities during the week. Five of the 12 participants had difficulties with understanding the introductory question: “what is your cultural background” in the original OPAQ. The interviews revealed that the participants recalling 7 days forgot to record some of the physical activity they had done during the week, indicating issues with the weekly recall method.

After transforming to the online version, this was reported to be easy and quick to fill in (taking 1–3 min per day), and participants reported the daily design was helpful to remember activities. There was good correspondence between the online version and objective actigraphs with a tendency to underreport. Six participants reported 10–60 min less moderate to vigorous physical activity compared to the actigraphs, while one participant reported 3 min more.

Conclusion

Participants found the online OPAQ quick and easy to complete during a 1-week period. Completing daily rather than weekly may help limit issues with recall. Overall, there was good agreement between the objective actigraphs and the OPAQ, though the OPAQ tended to slightly underreport moderate to vigorous physical activity.

The Danish online version of OPAQ may be useful for capturing school students’ physical activity when objective measures are not feasible.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01108-x.

Psychometric Parameters of the Intrinsic Motivation Inventory Adapted to Physical Education in a Sample of Active Adults from Austria

Introduction. Intrinsic motivation is essential for establishing life-long positive behaviors. In Physical Education (PE), this variable may have a significant impact on students’ choice of adhering to an active lifestyle both in the short and long term. Many tools have been developed for the assessment of intrinsic motivation, among which the Intrinsic Motivation Inventory (IMI) was built based on the Self-Determination Theory. The aim of this study is to examine a version of the IMI adapted to PE (IMI-PE). Methods. A total of 660 customers of a Sports Service Center responded to the IMI-PE and 39 individuals carried out a test–retest of the tool within two weeks. Results. The initial model including the original pool of items showed low indexes of goodness of fit. However, the removal of item 6, 8, 13, and 14 led to excellent parameters for the four-factor model (CFI = 0.96, and SRMR = 0.0420). Internal consistency and reliability analyses confirmed the robustness of such model. The final IMI-PE, comprising 14 items distributed into four factors, represents a robust assessment tool for the analysis of intrinsic motivation in PE.

Health Impact Assessment (HIA) of a Daily Physical Activity Unit in Schools: Focus on Children and Adolescents in Austria Up to the 8th Grade

Physical activity has a variety of health benefits for young people. The World Health Organization (WHO) recommends that children and adolescents aged 5-17 years should be physically active for at least 60 min a day. This Health Impact Assessment (HIA) examined the potential impact of a daily physical activity unit in Austrian schools, with a focus on children and adolescents up to eighth grade. The HIA methodology systematically followed several stages: screening and scoping, appraisal, and formulation of recommendations. A literature review, an online survey (n = 712), focus group discussions (n = 4), and appraisal workshops (n = 2) have been carried out. The analyzed results indicate a primarily positive impact on the individual health of children and adolescents, on social and community-related networks, on living and working conditions, and on the system level. Recommendations for the implementation include ensuring equal opportunities and support for disadvantaged children and schools. Furthermore, the comprehensible selection of pilot regions and the nationwide resource planning should be considered. Additional important factors include the education and further training of pedagogical staff and coaches, and the availability of sufficient infrastructure. In the long term, the fixed integration of five additional teaching units of physical activity per week, and an increased focus on the elementary/nursery school sector were identified as significant.

Physical Activity in Late Prepuberty and Early Puberty Is Associated With High Bone Formation and Low Bone Resorption

Background

Physical activity (PA) increases bone mass, especially in late prepuberty and early puberty, but it remains unclear if and how PA affects both bone formation and bone resorption.

Materials and Methods

We included 191 boys and 158 girls aged 7.7 ± 0.6 (mean ± SD) in a population-based PA intervention study. The intervention group (123 boys and 94 girls) received daily physical education (PE) in school (40 min/day; 200 min/week) from study start and during the nine compulsory school years in Sweden. The controls (68 boys and 64 girls) received the national standard of 1–2 classes PE/week (60 min/week). During the intervention, blood samples were collected at ages 9.9 ± 0.6 (n = 172; all in Tanner stages 1–2) and 14.8 ± 0.8 (n = 146; all in Tanner stages 3–5) and after termination of the intervention at age 18.8 ± 0.3 (n = 93; all in Tanner stage 5) and 23.5 ± 0.7 (n = 152). In serum, we analyzed bone formation markers [bone-specific alkaline phosphatase (bALP), osteocalcin (OC), and N-terminal propeptide of collagen type 1 (PINP)] and bone resorption markers [C-terminal telopeptide cross links (CTX) and tartrate-resistant acid phosphatase (TRAcP 5b)]. Linear regression was used to compare age and sex-adjusted mean differences between intervention children and controls in these markers.

Results

Two years after the intervention was initiated (at Tanner stages 1–2), we found higher serum levels of bALP and OC, and lower serum levels of TRAcP 5b in the intervention compared with the control group. The mean difference (95% CI) was for bALP: 13.7 (2.1, 25.3) μg/L, OC: 9.1 (0.1, 18.1) μg/L, and TRAcP 5b: −2.3 (−3.9, −0.7) U/L. At Tanner stages 3–5 and after the intervention was terminated, bone turnover markers were similar in the intervention and the control children.

Conclusion

Daily school PA in the late prepubertal and early pubertal periods is associated with higher bone formation and lower bone resorption than school PA 1–2 times/week. In late pubertal and postpubertal periods, bone formation and resorption were similar. Termination of the intervention is not associated with adverse bone turnover, indicating that PA-induced bone mass benefits gained during growth may remain in adulthood.

Physical Activity at Growth Induces Bone Mass Benefits Into Adulthood – A Fifteen‐Year Prospective Controlled Study

Daily school physical activity (PA) improves musculoskeletal traits. Whether or not benefits remain in adulthood is debated. We included in this study 131 children that took part in an intervention with 40 minutes of PA per school day (200 minutes per week) from age 6 to 9 years (grade one) to age 14 to 16 years (grade nine), whereas 78 children continued with national recommended school physical education of 60 minutes per week. Measurements were done with dual‐energy X‐ray absorptiometry (bone mineral content [BMC], bone mineral density [BMD], and bone area), and a computerized knee dynamometer (peak torque muscle strength) at study start, at the end of the intervention, and 7 years after the intervention. Group differences from study start and end of the intervention to 7 years thereafter were estimated by analyses of covariance (adjusted for sex and follow‐up time). Musculoskeletal gains from study start to 7 years after termination of the intervention were higher in the intervention group (total body less head BMC +182.5 g [95% confidence interval {CI}, 55.1–309.9] and BMD +0.03 g/cm² [95% CI, 0.003–0.05], femoral neck area + 0.2 cm² [95% CI, 0.1–0.4], and knee flexion peak torque muscle strength at 60 degrees per second +9.2 Nm [95% CI, 2.9–15.5]). There was no attenuation during the 7 years that followed termination of the intervention (all group comparisons p > 0.05). Benefits in musculoskeletal gains remain 7 years after termination of a daily school‐based PA program, without attenuation after termination of the program. Daily school PA may counteract low bone mass and inferior muscle strength in adulthood. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Influence of an increased number of physical education lessons on the motor performance of adolescents-A non-interventional cohort study

Increasing the amount of regular physical education lessons in school is currently discussed in many countries in order to increase physical activity in youth. The purpose of this study was to compare the motor performance of pupils from an observation group participating in a school trial of two additional physical education lessons (5 lessons of each 50 min/week) without a specific intervention program to a control group with a regular amount of three physical education lessons (3 lessons of each 50 min/week) as indicated by the standard Austrian school curriculum. In this cohort study motor performance of 140 adolescents (12.7±0.5 years) was assessed by means of the German Motor Performance Test 6–18 over a period of 1.5 years with measurement time points before (T1), after eight months (T2) and at the end of the observation period (T3). Two- and three-way mixed analysis of variance were used to detect time, group and interaction effects. Although the observation group demonstrated a higher total motor performance score at all time points (P = 0.005), the improvement over time in total motor performance (P < 0.001) was more pronounced in the control group. Girls and boys developed differently over time (time*gender interaction: P = 0.001), whereby group allocation did not affect this interaction (time*gender*group: P = 0.167). Anyway, girls of control group tend to benefit most of additional physical education lessons. Sports club members scored significantly higher in motor performance across the observation period (P = 0.018) irrespective of group allocation. These findings indicate that there could be a ceiling effect in what the pupils could achieve in terms of motor performance as the pupils of the observation group might have reached this point earlier than their counterparts in the control group. Nevertheless, sports club membership seems to reveal some benefits. Whether improving quality and specificity of the single physical lessons might be superior to merely adding additional ones needs to be confirmed in future studies.

Musculoskeletal Benefits from a Physical Activity Program in Primary School are Retained 4 Years after the Program is Terminated

Daily school physical activity (PA) improves musculoskeletal traits. This study evaluates whether the benefits remain 4 years after the intervention. We followed 45 boys and 36 girls who had had 40 min PA/school day during the nine compulsory school years and 21 boys and 22 girls who had had 60 min PA/school week (reference), with measurements at baseline and 4 years after the program terminated. Bone mineral content (BMC; g) and bone mineral density (BMD; g/cm²) were measured by dual-energy X-ray absorptiometry and knee flexion peak torque relative to total body weight (PT_flexTBW) at a speed of 180 degrees/second with a computerized dynamometer. Group differences are presented as mean differences (adjusted for sex and duration of follow-up period) with 95% confidence intervals. The total gain bone mass [mean difference in spine BMC +32.0 g (14.6, 49.4) and in arms BMD of +0.06 g/cm² (0.02, 0.09)] and gain in muscle strength [mean difference in PT_flex180TBW +12.1 (2.0, 22.2)] were greater in the intervention than in the control group. There are still 4 years after the intervention indications of benefits in both bone mass and muscle strength gain. Daily school PA may counteract low bone mass and inferior muscle strength in adult life. ClinicalTrials.gov.NCT000633828 retrospectively registered 2008-11-03.

Daily Physical Education Linked to Higher Youth Aerobic Fitness Levels: A 4-Year Longitudinal Study

PURPOSE

Physical education (PE) provides opportunities for youth physical activity during the school day, yet daily PE policies remain low. This study investigated whether daily PE was linked to youth aerobic capacity across a 4-year period in Greenville (South Carolina).

METHODS

Youth in grade levels second to eighth at 2 schools providing daily PE and 2 schools that did not provide daily PE participated in the study (N = 466). The 2 schools used as comparisons provided standard PE outlined by South Carolina, which included one 50-minute session per week (elementary) and daily PE for one semester (middle school). Aerobic fitness was measured using the FITNESSGRAM® Progressive Aerobic Cardiovascular Endurance Run test (May 2011-2015). Number of Progressive Aerobic Cardiovascular Endurance Run laps completed, age, gender, ethnicity, body composition, and school attended were included in multilevel linear regression analyses.

RESULTS

Across the sample, aerobic fitness increased with age. Throughout the study, males demonstrated growth in aerobic fitness compared with a slight decline for females (P < .001). Youth participation in daily PE was linked to increases in aerobic fitness compared with youth who did not receive daily PE (P < .001).

CONCLUSIONS

Findings suggest that exposure to daily PE may contribute to increased aerobic fitness in youth.

Physical exercise is associated with beneficial bone mineral density and body composition in young adults with childhood-onset inflammatory bowel disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) have an increased risk of compromised bone mineral density (BMD) and body composition. There are limited data on the physical exercise (PE) habits of patients with childhood-onset IBD and on the associations between PE and BMD and body composition.

PATIENTS AND METHODS

In total, 72 young adults with childhood-onset IBD and 1341 normative young adult controls answered questionnaires regarding PE [hours/week (h/w)] in the last 12 months. BMD and body composition were measured with dual x-ray absorptiometry (DXA) and presented as age- and gender-adjusted Z-scores for BMD, skeletal muscle index (SMI, the weight of lean mass in arms and legs/m²), and percentage body fat (Fat %).

RESULTS

A total of 41 (57%) patients with IBD engaged in PE during the previous 12 months, as compared to 913 (68%) of the controls (p = .053). Sedentary patients had significantly lower median BMD, SMI, and Fat % Z-scores than the controls with corresponding PE habits (all p < .05). In contrast, highly active (>4 h/week) patients had total body BMD, SMI, and Fat % in the same range as the controls with corresponding PE levels (p = .151, p = .992, and p = .189, respectively), albeit with lower BMDs in the spine (p = .007) and femoral neck (p = .015). Using multiple regression analyses, a diagnosis of childhood-onset IBD was independently associated with inferior BMD and body composition, regardless of the amount of PE.

CONCLUSION

Physical exercise is associated with beneficial bone mineral density and body composition in patients with IBD despite the negative effects of the disease.

The relationship between healthy lifestyles and bone health: A narrative review

BACKGROUND

Bone health, especially osteoporosis among ageing populations, has become an important topic for both clinical and basic researchers. The relationship between bone health and healthy lifestyles has been frequently discussed. The present study focuses on the relationship between bone health and healthy lifestyles among older adults, based on a global comparison.

METHODS

This narrative review was performed by collecting clinical trials, basic research and reviews on lifestyle and bone health in PubMed database.

RESULTS

Positive effects of physical activity and negative effects of malnutrition, alcohol abuse, and cigarette smoking on bone health were revealed. The relationship between bone health and drinking coffee and tea is still inconclusive. Moreover, the diversity of each region should be aware when considering healthy lifestyles to improve bone health.

CONCLUSION

Healthy lifestyles are highly related to bone health, and different lifestyles may have different influences on regions with a high risk of bone diseases. It is practical to acknowledge the diversity of economic, religious, environmental and geological conditions in each region when providing suitable and effective recommendations for healthy lifestyles that can improve overall bone health.

Effect of Linear and Nonlinear Pedagogy Physical Education Interventions on Children's Physical Activity: A Cluster Randomized Controlled Trial (SAMPLE-PE)

Background: School-based interventions are a key opportunity to improve children’s physical activity (PA); however, there is lack of evidence about how pedagogical approaches to motor learning in physical education (PE) might affect PA in children. Therefore, this study aimed to assess how different pedagogical approaches in PE might affect children’s PA. Methods: Participants (n = 360, 5–6 years) from 12 primary schools within the SAMPLE-PE randomized controlled trial were randomly allocated to either Linear Pedagogy (LP: n = 3) or Nonlinear Pedagogy (NP: n = 3) interventions, where schools received a 15-week PE intervention delivered by trained coaches, or to a control group (n = 6), where schools followed usual practice. ActiGraph GT9X accelerometers were used to assess PA metrics (moderate-to-vigorous PA, mean raw acceleration and lowest acceleration over the most active hour and half hour) over whole and segmented weeks at baseline, immediately post-intervention and 6 months follow-up. Intention to treat analysis employing multilevel modelling was used to assess intervention effects. Results: LP and NP interventions did not significantly affect children’s PA levels compared to the control group. Conclusion: PE interventions based on LP and NP alone might not be effective in improving habitual PA in children.

Improving musculoskeletal health for children and young people - A 'call to action'

This chapter describes the musculoskeletal (MSK) context in children and young people as an important contributor to the global non-communicable disease burden. Through selected MSK conditions, we describe the impact on patients, families and communities and highlight the challenges that need to be addressed. We focus on opportunities for better working together and describe exemplar initiatives to raise awareness, workforce capacity building, models of care and research agendas to have a greater global context.

Promoting Health-Related Cardiorespiratory Fitness in Physical Education: The Role of Class Intensity and Habitual Physical Activity

Physical education (PE) has the potential to promote health-related fitness, however, its contribution is still not clear. The aim of this study was to assess whether students’ health-related cardiorespiratory fitness (CRF) improved from the beginning to the end of the school year, and to examine the role of PE class intensity and habitual physical activity (PA) in promoting students’ CRF. This observational study employed a longitudinal design. Participants were 212 7th and 8th grade students (105 boys), mean age 12.9 years old, followed during one school year, from September 2017 to June 2018. The Progressive Aerobic Cardiovascular Endurance Run (PACER) was used to assess CRF at baseline and follow-up. PA was measured using accelerometers. PE class intensity was assessed using the System for Observing Fitness Instruction Time. Findings indicated that from the beginning to the end of the school year, a greater percentage of participants were in the CRF healthy fitness zone (73.1% to 79.7%, p = 0.022). Among boys, participating in organized sports (B = 4.61, 95% confidence interval [CI]: 0.33, 8.88) and the percentage of PE time being very active (B = 0.90, 95% CI: 0.44, 1.35) were positively associated with the change in PACER laps. Among girls, daily vigorous PA (B = 0.38, 95% CI: 0.15, 0.60) and participating in organized sports (B = 4.10, 95% CI: 0.93, 7.27) were also positively associated with PACER change, while being overweight or obese (B = −5.11, 95% CI: −8.28, −1.93) was negatively associated. In conclusion, PE was demonstrated to have a positive role in the promotion of CRF, especially among boys, while for girls, habitual PA seems to have a greater contribution. Nevertheless, results and conclusions should be considered carefully, taking into account study limitations, such as the non-direct measures of PE class intensity, CRF, and school setting.

Can School-Based Physical Activity Projects Such as Skipping Hearts Have a Long-Term Impact on Health and Health Behavior?

Low physical activity, limited motor skills, and an increased number of overweight or obese children are major public health problems. Numerous school-based programs try to improve physical activity and health behavior in children but investigations on sustainable effects of these programs are rare. Therefore, we examined the long-term effects of the Skipping Hearts health promotion project. 486 children (57.7% female, 9.0 ± 0.6 years at baseline) participated in this non-randomized controlled longitudinal trial within a follow-up period of 3.5 years. Of these, 286 subjects received a one-time 90-min workshop in rope skipping (Basic-Workshop) and 140 additionally received 10 lessons in rope skipping (Champion-Program), 78 students served as controls. Anthropometrics, blood pressure, motor skills, screen-based media use, self-assessment of physical fitness, and physical activity were collected at both measurement points; endurance capacity and health-related quality of life only at follow-up. Standard deviation scores of body-mass-index (η2 = 0.005) and systolic blood pressure (η2 = 0.006) decreased, while diastolic blood pressure (η2 = 0.004), motor performance (η2 < 0.001), physical fitness, subjective physical activity (η2 = 0.008), and screen-based media use (η2 = 0.001) increased without significant difference in development between groups (all p > 0.05). At follow-up, groups did not differ in endurance capacity (η2 = 0.010) and health-related quality of life (η2 < 0.001). Skipping Hearts does not affect the long-term improvement of health status, motor performance, or health behavior. To improve the effects, the project should be implemented as a daily routine in schools to force the transfer of health behavior-related knowledge. Nevertheless, the project offers a physical activity that can be performed in children's everyday life without high costs.

A Comparative Study of Participation in Physical Education Classes among 170,347 Adolescents from 54 Low-, Middle-, and High-Income Countries

Given the need for comparative research on the participation of adolescents in physical education (PE) classes as a privileged space for physical activity (PA) promotion, this study sought to estimate, analyse and compare the prevalence of participation in PE classes among adolescents from 54 countries and to examine sex, age, country income and world regions disparities. Data from the Global Students Health Survey (2010–2015) were used, comprising 170,347 adolescents (90,305 girls, aged 13–17 years) from nationally representative samples of 54 countries—of which 7 are low-income, 23 lower-middle-income, 14 upper-middle-income and 10 high-income—and six world regions. The weighted percentages of adolescents participating in PE classes (never, 1–2 days/week, 3–4 days/week, 5 or more days/week) were estimated along 95% confidence intervals and compared across sex, age, country income, region, and country. Most adolescents reported to participate in PE on 1–2 days/week (55.2%), but almost 20% of adolescents reported never participating in PE. Girls, compared to boys, presented a lower prevalence for participating ≥5 days/week (girls 16.8%, boys 20.0%). The prevalence of participating in PE on ≥3 days/week was higher among adolescents aged 13–14 years when compared to adolescents aged 15–17 years (boys: 30.9% vs. 24.6%; girls: 26.1% vs. 18.2%). Concerning the countries’ income, the prevalence of never participating in PE was higher in high-income countries, and participating on ≥3 days/week was higher in low-income countries, but further research is recommended. The findings suggest that national, regional and worldwide data highlight the importance of improving participation in PE, particularly for girls and older adolescents. An improved and continued monitoring of PE policies and their actual implementation is needed worldwide.

Daily School Physical Activity Is Associated with Higher Level of Physical Activity Independently of Other Socioecological Factors

Only one fifth of children aged 11–17 years are physically active for 60 min (min)/day. As physical activity (PA) levels track from childhood to adulthood, it is important to establish healthy PA behavior early in life. This study aims to evaluate whether daily school PA is associated with objectively measured PA independently of other socioecological factors. This study includes 209 children (120 boys) aged 9.8 ± 0.6 (mean ± SD) years from four government-funded schools in Sweden. One school including 113 children (70 boys) had 40 min of daily school PA (intervention) and three schools including 96 children (50 boys) had 60 min of school PA/week (control). PA was measured during four serial days with accelerometers. General PA (GPA) was defined as mean counts per minute (cpm). Socioecological factors were collected by questionnaires, and anthropometric traits by measurements. Analysis of covariance (ANCOVA) was used to test whether sex, age, relative age, body height, fat mass, lean mass, screen time activity, parental educational level, parental attitude towards PA, parental PA, sibling(s)’ PA, living in a house or apartment, and whether the child was allocated to 40 min daily school PA or 60 min school PA/week, was independently associated with GPA. Daily GPA was found to be 686.9 ± 211.9 cpm. Independently of the other included factors, daily school PA was associated with +81.8 (15.7, 147.8) cpm compared with 60 min PA/week. This study infers that daily school PA is an appropriate strategy to promote PA in 10-year-old children, independently of different socioecological factors.

Daily School Physical Activity from Before to After Puberty Improves Bone Mass and a Musculoskeletal Composite Risk Score for Fracture

This 7.5-year prospective controlled exercise intervention study assessed if daily school physical activity (PA), from before to after puberty, improved musculoskeletal traits. There were 63 boys and 34 girls in the intervention group (40 min PA/day), and 26 boys and 17 girls in the control group (60 min PA/week). We measured musculoskeletal traits at the start and end of the study. The overall musculoskeletal effect of PA was also estimated by a composite score (mean Z-score of the lumbar spine bone mineral content (BMC), bone area (BA), total body lean mass (TBLM), calcaneal ultrasound (speed of sound (SOS)), and muscle strength (knee flexion peak torque)). We used analyses of covariance (ANCOVA) for group comparisons. Compared to the gender-matched control group, intervention boys reached higher gains in BMC, BA, muscle strength, as well as in the composite score, and intervention girls higher gains in BMC, BA, SOS, as well as in the composite score (all p < 0.05, respectively). Our small sample study indicates that a daily school-based PA intervention program from Tanner stage 1 to 5 in both sexes is associated with greater bone mineral accrual, greater gain in bone size, and a greater gain in a musculoskeletal composite score for fractures.

Socioecological and biological associations of lower levels of physical activity in 8-year-old children: a 2-year prospective study

OBJECTIVES

Evaluate if socioecological and biological factors, at the age of 8 years, are associated with lower level of physical activity (PA) 2 years later.

METHOD

In a study cohort of 199 children aged 7.8±0.6 years, we used questionnaires and physical measurements to evaluate biological (eg, sex), social (eg, parental PA) and environmental (eg, school settings) factors. Objective PA was measured 2 years later with accelerometers. General PA (GPA) was defined as mean counts per minute (cpm) and moderate to vigorous PA (MVPA) as min/day >3500 cpm. We used analysis of covariance to evaluate if socioecological factors at age 8 are associated with level of PA 2 years later.

RESULTS

Daily GPA was 690.5±216.6 cpm and the children spent 40.9±18.3 min on MVPA. Female sex is associated with -131.1 (-183.4, -78.7) cpm GPA, each 10 cm shorter body height with -48.7 (-94.8, -26.5), each unit higher body mass index (BMI) with -26.0 (-37.5, -14.5) and allocation to 60 min school PA/week with -73.8 (-131.5, -16.2) compared with allocation to 200 min school PA/week. Female sex is associated with -10.3 (-14.8, -5.7) min of MVPA and each unit higher BMI with -1.9 (-2.9, -0.9) min.

CONCLUSION

Female sex, shorter body height and higher BMI are at age 8 years associated with lower level of PA 2 years later. It appears possible to increase PA by daily school PA.

TRIAL REGISTRATION NUMBER

NCT00633828.