Grant Tomkinson

What proportion of youth are physically active? Measurement issues, levels and recent time trends

Aim The aim of this review is to summarise issues surrounding the measurement of physical activity (PA) by self-report and accelerometry in youth (2–18 years old). Current levels and temporal trends in PA and sport participation and the effect of assessment method on data interpretation will be summarised. Methods Relevant papers were extracted from a computerised literature search of MEDLINE and personal databases. Additional papers were extracted from reference lists of recently published reviews. Results The criterion validity (direct comparison with an objective method) of self-reported instruments is low to moderate, with correlation coefficients generally between 0.3 and 0.4. Self-report instruments overestimate the intensity and duration of PA and sport participation. The interpretation of PA data from accelerometry is a challenge, and specific issues include the definition of intensity thresholds and the influence of age on intensity thresholds. Recent data on self-reported PA in youth suggest that between 30% and 40% are sufficiently active. Prevalence values for sufficiently active youth measured by accelerometry range between 1% and 100%, depending on the intensity thresholds used. Sport participation is likely to contribute to higher levels of PA. The available evidence does not support the notion that PA levels and sport participation in youth have declined in recent decades. Conclusion The number of youth meeting current PA guidelines varies by assessment method and the intensity thresholds used when PA is measured by accelerometry. The available evidence does not firmly support the notion that PA in young people has declined during the last decades. It is unlikely that any self-report method is sufficiently accurate for examining cross-cultural differences and temporal trends in young peoples PA and sport participation over time. Surveillance systems therefore need to strive for an international standardisation using objective measurements of PA to complement existing self-report instruments.

Trends in the prevalence of childhood overweight and obesity in Australia between 1985 and 2008

Background:Popular media, health experts and researchers talk about a paediatric ‘obesity epidemic’ with exponentially increasing rates of obesity and overweight. However, some recent reports suggest that prevalence may have plateaued. This study examined trends in the prevalence of Australian childhood overweight and obesity since 1985. Specifically, it aimed to determine whether there have been (a) overall increases in average body mass index (BMI), (b) differential patterns of change within age groups and (c) increases in BMI within each weight-status category.Method:Forty-one Australian studies of childhood weight status conducted between 1985 and 2008 were reviewed. The studies included data on 264 905 Australians aged 2–18 years, with raw data being available on 70 758 children (27%). Children were classified as overweight or obese based on BMI using the criteria of Cole et al. (BMJ, 2000). The prevalence estimates were adjusted for age and sex, and plotted against measurement year using Lowess plots and two-linear-segment models. Where raw data were available, BMI z-scores (UK 1990 standard) were plotted against measurement year for all children and children in various age groups. Lowess plots and two-linear-segment models were used to assess secular trends in BMI z-scores pre- and post-1996 within age, gender and weight-status categories.Results:There has been a plateau, or only slight increase, in the percentage of boys and girls classified as overweight or obese, with almost no change over the last 10 years. In boys and girls, prevalence rates have settled around 21–25% for overweight and obesity together, and 5–6% for obesity alone. Similar trends were found for BMI z-scores. These patterns were fairly consistent across the age span. Within each weight-status category, average BMI has not increased.Conclusions:Although levels of Australian paediatric overweight remain high, the prevalence of overweight and obesity seems to have flattened and has not followed the anticipated exponential trajectory.

Physical Activity of Children: A Global Matrix of Grades Comparing 15 Countries

The Active Healthy Kids Canada (AHKC) Report Card on Physical Activity for Children and Youth has been effective in powering the movement to get kids moving by influencing priorities, policies, and practice in Canada. The AHKC Report Card process was replicated in 14 additional countries from 5 continents using 9 common indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behavior, Family and Peers, School, Community and Built Environment, and Government Strategies and Investments), a harmonized process and a standardized grading framework. The 15 Report Cards were presented at the Global Summit on the Physical Activity of Children in Toronto on May 20, 2014. The consolidated findings are summarized here in the form of a global matrix of grades. There is a large spread in grades across countries for most indicators. Countries that lead in certain indicators lag in others. Overall, the grades for indicators of physical activity (PA) around the world are low/poor. Many countries have insufficient information to assign a grade, particularly for the Active Play and Family and Peers indicators. Grades for Sedentary Behaviors are, in general, better in low income countries. The Community and Built Environment indicator received high grades in high income countries and notably lower grades in low income countries. There was a pattern of higher PA and lower sedentary behavior in countries reporting poorer infrastructure, and lower PA and higher sedentary behavior in countries reporting better infrastructure, which presents an interesting paradox. Many surveillance and research gaps and weaknesses were apparent. International cooperation and cross-fertilization is encouraged to tackle existing challenges, understand underlying mechanisms, derive innovative solutions, and overcome the expanding childhood inactivity crisis.

International olympic committee consensus statement on the health and fitness of young people through physical activity and sport

The International Olympic Committee (IOC) recognises the health and fitness benefits of physical activity (PA) and sport as stated in recommendation #51 from the Olympic Movement in Society Congress held in Copenhagen, 2009: Everyone involved in the Olympic Movement must become more aware of the fundamental importance of Physical Activity and sport for a healthy lifestyle, not least in the growing battle against obesity, and must reach out to parents and schools as part of a strategy to counter the rising inactivity of young people.1 The IOC assembled an expert group (January 2011) to discuss the role of PA and sport on the health and fitness of young people and to critically evaluate the scientific evidence as a basis for decision making. Specifically, the purpose of this consensus paper is to identify potential solutions through collaboration between sport and existing programmes and to review the research gaps in this field. The ultimate aim of the paper is to provide recommendations for young peoples sport and PA stakeholders. After an introduction to the scope of the problem, issues addressed include how best to define the current state of …

Normative health-related fitness values for children: analysis of 85347 test results on 9–17-year-old Australians since 1985

Objectives To provide sex- and age-specific normative values for health-related fitness of 9–17-year-old Australians. Methods A systematic literature search was undertaken to identify peer-reviewed studies reporting health-related fitness data on Australian children since 1985—the year of the last national fitness survey. Only data on reasonably representative s amples of apparently healthy (free from known disease or injury) 9–17-year-old Australians, who were tested using field tests of health-related fitness, were included. Both raw and pseudo data (generated using Monte Carlo simulation) were combined with sex- and age-specific normative centile values generated using the Lambda Mu and Sigma (LMS) method. Sex- and age-related differences were expressed as standardised effect sizes. Results Normative values were displayed as tabulated percentiles and as smoothed centile curves for nine health-related fitness tests based on a dataset comprising 85347 test performances. Boys typically scored higher than girls on cardiovascular endurance, muscular strength, muscular endurance, speed and power tests, but lower on the flexibility test. The magnitude of the age-related changes was generally larger for boys than for girls, especially during the teenage years. Conclusion This study provides the most up-to-date sex- and age-specific normative centile values for the health-related fitness of Australian children that can be used as benchmark values for health and fitness screening and surveillance systems.

Three-dimensional anthropometric analysis: Differences between elite Australian rowers and the general population

Abstract The aim of this study was to quantify the anthropometric differences between elite senior Australian rowers and the Australian adult population using three-dimensional (3D) whole-body scanning. The dimensions of senior rowers competing at the 2007–2008 Australian Rowing Championships were compared with those of an age-matched sample of Australian adults. Mass, height, and sitting height were measured before the participants underwent a 3D whole-body scan, with lengths, breadths, girths, cross-sectional and surface areas, and volumes extracted from each scan. Differences in means and variability between the two groups were expressed as standardized effect sizes and ratios of coefficients of variation. Heavyweight rowers were generally much larger than the general population in absolute size, with 3D dimensions and height and mass showing the largest effects. In contrast, lightweight rowers were generally similar or smaller in absolute and proportional size. The dimensions of rowers, especially the lightweights, were also generally less variable than those of the general population. The greatest differences between elite rowers and the general population were seen in dimensions that could not be captured without 3D scanning, such as segmental volumes and cross-sectional areas.

Bilateral symmetry and the competitive standard attained in elite and sub-elite sport.

Abstract Deviations from perfect bilateral symmetry, in a normally symmetric organism, signal a lack of developmental precision. In adult human males, previous studies have shown that symmetry is positively associated with height, body mass and physical performance. In this study, symmetry was measured in adult male athletes from two sports, competing at two different standards. Fifty-two elite and sub-elite Australian male basketballers and soccer players, who regularly competed in the national and state leagues in the 2000–2001 season, participated in the study. All participants underwent anthropometric assessment. Both basketballers and national league athletes in general were significantly taller (P<0.0001) and heavier (P<0.001) (and more ectomorphic in the case of basketballers) than their soccer-playing and state league counterparts, respectively. The anthropometric traits were examined further for departures from perfect bilateral symmetry. No significant differences in size-corrected asymmetry were observed between the two competitive standards (P>0.50), the two sports (P>0.50) or among any of the competitive standard × sport groups (P>0.50). Contrary to expectations, we did not find any differences in asymmetry between adult male athletes from two sports (basketball and soccer), competing at two different standards (professional national league and semi-professional state league).

Temporal Changes in Long-Distance Running Performance of Asian Children between 1964 and 2009

Aerobic fitness is considered to be an important marker of current health and even a predictor of future health. The aim of this study was to system- atically analyse the available scientific information on temporal changes in maximal long-distance running performance (a widely and long-used marker of aerobic fitness) of Asian children. A systematic review of the scientific literature was undertaken to locate studies explicitly reporting on temporal changes (spanning a minimum of 5 years) in maximal long-distance running of apparently healthy (free fromknown disease or injury) Asian children aged 9–17 years. Studies were located up to October 2010 via computerized searching of bibliographical databases, reference list searching and personal communication with international experts. Temporal changes were analysed at the country by sex by age by test level using best-fitting linear or polynomial

Results from Australia’s 2014 Report Card on Physical Activity for Children and Youth

BACKGROUND Like many other countries, Australia is facing an inactivity epidemic. The purpose of the Australian 2014 Physical Activity Report Card initiative was to assess the behaviors, settings, and sources of influences and strategies and investments associated with the physical activity levels of Australian children and youth. METHODS A Research Working Group (RWG) drawn from experts around Australia collaborated to determine key indicators, assess available datasets, and the metrics which should be used to inform grades for each indicator and factors to consider when weighting the data. The RWG then met to evaluate the synthesized data to assign a grade to each indicator. RESULTS Overall Physical Activity Levels were assigned a grade of D-. Other physical activity behaviors were also graded as less than average (D to D-), while Organized Sport and Physical Activity Participation was assigned a grade of B-. The nation performed better for settings and sources of influence and Government Strategies and Investments (A- to a C). Four incompletes were assigned due to a lack of representative quality data. CONCLUSIONS Evidence suggests that physical activity levels of Australian children remain very low, despite moderately supportive social, environmental and regulatory environments. There are clear gaps in the research which need to be filled and consistent data collection methods need to be put into place.

Quantification of the postural and technical errors in asymptomatic adults using direct 3D whole body scan measurements of standing posture

Measurement repeatability has important decision-making implications for clinicians and researchers when assessing individuals. The aims of this study were to quantify: (a) the repeatability of direct measurements of standing posture using three dimensional (3D) whole body scanning, and (b) the magnitude of the postural and technical errors involved. Fifty-two asymptomatic adults were scanned twice, 24h apart, using the Vitus Smart 3D whole body scanner. Eleven clinically relevant standing postural measurements were calculated from scan-extracted data. The process was repeated with 10 shop mannequins. Systematic error was expressed as absolute changes in means and as standardised effect sizes, with random (within-subject) error expressed as the typical error. Technical error was calculated as the typical error in the measurement of mannequins; total error as the typical error in the measurement of subjects; and postural error as the square root of the difference between the squared total error and the squared technical error. Most standing postural measurements demonstrated good repeatability, with median (95% CI) systematic and random errors of -0.1° (1.1°) and 2.8° (1.9°), respectively. However, head and neck postures demonstrated poor repeatability due to large random errors brought about by large postural errors. Overall, most of the error was due to postural error rather than technical error. The relatively small technical errors highlight that this 3D measurement process is generally repeatable, while the relatively large postural errors related to the head and neck suggest that these postures probably lack the precision to be clinically useful using this procedure.