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Cited by 828Physical Activity and HealthObesity, Physical Activity, DietContext-Aware Activity Recognition Systems

Objectively measured physical activity and sedentary time in youth: the International Children's Accelerometry Database (ICAD)

Open access
Cooper, Ashley R., Goodman, Anna, Page, Angie S., Sherar, Lauren B., Esliger, Dale W., van Sluijs, Esther MF, Andersen, Lars Bo, Anderssen, Sigmund +14 more·2015·International Journal of Behavioral Nutrition and Physical Activity
DOI 10.1186/s12966-015-0274-5PMC PMC4574095
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Abstract

BACKGROUND: Physical activity and sedentary behaviour in youth have been reported to vary by sex, age, weight status and country. However, supporting data are often self-reported and/or do not encompass a wide range of ages or geographical locations. This study aimed to describe objectively-measured physical activity and sedentary time patterns in youth. METHODS: The International Children's Accelerometry Database (ICAD) consists of ActiGraph accelerometer data from 20 studies in ten countries, processed using common data reduction procedures. Analyses were conducted on 27,637 participants (2.8-18.4 years) who provided at least three days of valid accelerometer data. Linear regression was used to examine associations between age, sex, weight status, country and physical activity outcomes. RESULTS: Boys were less sedentary and more active than girls at all ages. After 5 years of age there was an average cross-sectional decrease of 4.2% in total physical activity with each additional year of age, due mainly to lower levels of light-intensity physical activity and greater time spent sedentary. Physical activity did not differ by weight status in the youngest children, but from age seven onwards, overweight/obese participants were less active than their normal weight counterparts. Physical activity varied between samples from different countries, with a 15-20% difference between the highest and lowest countries at age 9-10 and a 26-28% difference at age 12-13. CONCLUSIONS: Physical activity differed between samples from different countries, but the associations between demographic characteristics and physical activity were consistently observed. Further research is needed to explore environmental and sociocultural explanations for these differences.

AI snapshot

Written from the paper’s full text.

TL;DR

This pooled analysis of ActiGraph accelerometer data from 20 studies in ten countries described physical activity and sedentary time in 27,637 youth aged 2.8–18.4 years. It found consistent sex, age, and weight-status differences, plus substantial between-country variation, despite use of common data-reduction procedures.

Key findings

  • Boys were less sedentary and more active than girls at all ages. After age 5, total physical activity decreased cross-sectionally by an average of 4.2% per additional year (3.7% in boys, 4.6% in girls), mainly through lower light-intensity activity and greater sedentary time.
  • Physical activity did not differ by weight status in the youngest children, but from age seven onwards overweight/obese participants were less active than normal-weight peers; this showed a dose–response relationship in both sexes and was particularly large in boys.
  • Between-country differences were substantial: at age 9–10 the difference between the least active population (Madeira) and most active (Oslo, Norway) was 15–20% (156 cpm in boys, 613 vs. 769; 99 cpm in girls, 561 vs. 660), and at age 12–13 it was 26–28%.
  • Among 5–17 year olds in ICAD, only 9.0% of boys and 1.9% of girls achieved ≥60 min MVPA every valid day; ≥60 min MVPA was accumulated on 46% of valid days for boys and 22% for girls, with Norwegian boys aged 9–10 recording the highest values (60.5% of measured days).

Methods

  • ICAD pooled ActiGraph accelerometer data from 20 studies in ten countries using a standard data-reduction procedure. Analyses included 27,637 participants (92% of 29,967 potential participants) aged 2.8–18.4 years with at least 3 valid days (mean 5.3, range 3–7), providing 188,416 valid days across 35,360 time points.
  • Linear regression examined cross-sectional associations between age, sex, weight status, and physical activity outcomes, adjusted for study and season; robust standard errors accounted for repeated measures within participants. Country comparisons were restricted to ages 9–15 and ten studies from eight countries, using standardized within-country outcomes and random-effects meta-analysis.
  • Physical activity outcomes included average accelerometer counts per minute (cpm) and percentage time sedentary (≤100 cpm), light (101–2295 cpm), and moderate-to-vigorous (≥2296 cpm). Guideline achievement was presented as ≥60 min MVPA on every valid day and as the percentage of valid days with ≥60 min MVPA.

Limitations

  • The paper states that the sample was skewed toward ages 9–15 (82% of measurement time points) and the UK and USA (73% of measurement time points); some countries had too few participants for country-level analysis, countries were not globally representative, and low- and middle-income countries were underrepresented. Most samples were not nationally representative, though generally at least regionally representative.
  • The paper states accelerometer limitations: waist-worn accelerometers poorly record upper-body activity and cycling, potentially underestimating activity in high-cycling countries such as Denmark; they misclassify motionless-standing as sedentary, potentially overestimating sedentary time; and the MVPA thresholds perform poorly for ages 4–6 and are not validated under age 4.
  • The paper notes that direction of causation between weight status and physical activity was not investigated and may be bidirectional, and that individual, social, and environmental explanations for between-country differences were not explored. Evident from the text: girls were over-represented (59%, falling to 52% after excluding one large study of adolescent girls), which may affect descriptive proportions.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1186/s12966-015-0274-5

Cites

37 of 37 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 6 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    At age 9-10, the difference between the least active population (Madeira) and the most active (Oslo, Norway) was 15-20% (156 cpm in boys and 99 cpm in girls).

    “At age 9–10, the difference between the least active population (Madeira) and the most active (Oslo, Norway) was 15–20 % (156 cpm in boys (613 vs. 769) and 99 cpm in girls (561 vs. 660)).”
    Quote in the paperNot a substantial claim
  • Findingown data

    At age 12-13, differences between the highest and lowest countries were 26-28%.

    “At age 12–13, even larger differences were seen (26–28 % between the highest and lowest countries).”
    Quote in the paperNot a substantial claim
  • Findingown data

    The age-related decrease in total physical activity was mainly due to lower levels of light-intensity physical activity and greater time spent sedentary.

    “due mainly to lower levels of light-intensity physical activity and greater time spent sedentary”
    • Also stated in: § Physical activity by sex, age and weight status · plain
      “Simultaneous with the reduction in total physical activity and percentage time in MVPA between increasing age groups, light physical activity (Fig. 1c) declined and sedentary time increased (Fig. 1d).”
    • Also stated in: § Discussion · plain
      “the lower levels of overall physical activity with increasing age were reflected by a progressive increase in the volume of sedentary time and an almost equivalent ‘displacement’ of light-intensity physical activity.”
    Quote in the paperSubstantial claim
  • Findingown data

    Overweight/obesity was not associated with total physical activity in children aged 2-6.

    “Overweight/obesity was not associated with total physical activity in the youngest age groups (age 2–6)”
    • Also stated in: § Results · plain
      “Physical activity did not differ by weight status in the youngest children”
    Quote in the paperSubstantial claim
  • Findingown data

    From age 7 onwards, overweight/obese participants were less active than their normal weight counterparts.

    “but from age seven onwards, overweight/obese participants were less active than their normal weight counterparts.”
    • Also stated in: § Physical activity by sex, age and weight status · plain
      “but was consistently associated with lower total physical activity in older age groups (Fig. 2a).”
    Quote in the paperSubstantial claim
  • May combine two claims. 21
  • Classified as probably not a substantial claim. 6

  • May combine two claims.

    Findingown data

    The association between overweight/obesity and lower total physical activity in older children showed a dose-response relationship in both sexes and was particularly large in boys.

    “This association showed a dose–response relationship in both sexes, and was particularly large in boys (Fig. 2b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There was no country in which the sex difference in physical activity was not significant or where the point estimate was less than 0.2 SD.

    “there was no country in which this difference was not significant or where the point estimate for the difference was less than 0.2 standard deviations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Higher BMI was associated with lower physical activity in most countries, but this difference was not significant in all samples, including the two most active samples at age 9-10.

    “Higher BMI was associated with lower physical activity in most countries, but this difference was not significant in all samples, including the two most active samples at age 9–10 (Fig 5c).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The three countries represented twice were ranked in the same order, with the USA least active, England intermediate and Australia most active.

    “The three countries that were represented twice were ranked in the same order, with the USA least active, England intermediate and Australia most active.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Boys were less sedentary and more active than girls at all ages.

    “Boys were less sedentary and more active than girls at all ages.”
    • Also stated in: § Physical activity by sex, age and weight status · plain
      “Boys were more active and less sedentary than girls at all ages.”
    • Also stated in: § Discussion · plain
      “Physical activity was consistently lower in girls than boys”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In all countries, boys were more active than girls; on average, activity levels among boys were 0.45 SD higher than in girls at age 9-10 and 0.66 SD higher at age 12-13.

    “In all countries, boys were more active than girls. On average, activity levels among boys were 0.45 standard deviations higher than in girls at age 9–10 and 0.66 standard deviations higher at age 12–13 (Fig. 5a).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Physical activity varied substantially between countries, with a 15-20% difference between the highest and lowest countries at age 9-10 and a 26-28% difference at age 12-13.

    “Physical activity varied between samples from different countries, with a 15–20 % difference between the highest and lowest countries at age 9–10 and a 26–28 % difference at age 12–13.”
    • Also stated in: § Cross-country comparisons of physical activity · plain
      “Average accelerometer counts per minute varied substantially between countries, both at age 9–10 (Fig. 3a) and age 12–13 (Fig. 3b).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    There are many possible individual, social and environmental explanations for between-country differences that were not explored in this study.

    “There are many possible individual, social and environmental explanations for these differences that were not explored in this study.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductnone given

    The ICAD provides a large volume of accelerometer data reduced using a common protocol, which allows comparison of study samples from a number of countries.

    “The ICAD provides a large volume of accelerometer data reduced using a common protocol, which allows comparison of study samples from a number of countries.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    The countries included are not globally representative, with the US, UK and Northern Europe over-represented, few data from other geographical regions, and a dearth of data from low and middle-income countries.

    “the countries included are not globally representative, with the US, UK and Northern Europe over-represented, few data from other geographical regions, and a dearth of data from low and middle-income countries.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductcitation

    Waist-worn accelerometers mis-classify time spent in motionless-standing as sedentary, potentially leading to overestimates of the true volume of sedentary time.

    “In addition, waist-worn accelerometers mis-classify time spent in motionless-standing as sedentary, which is not considered to be a sedentary behaviour (defined as “any waking behaviour characterised by an energy expenditure ≤1.5 metabolic equivalents (METs) while in a sitting or reclining posture” [35]), potentially leading to over estimates of the true volume of sedentary time.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Network SBR. Letter to the Editor: Standardized use of the terms “sedentary” and “sedentary behaviours”. Appl Physiol Nutr Metab. 2012;37:540–2. source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    The number of participants in some countries did not allow analysis by country, and the sample is skewed towards two main age groups.

    “the number of participants in some countries did not allow analysis by country, and overall the sample is skewed towards two main age groups.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductnone given

    Most samples are not nationally representative, although studies have generally sampled to be at least regionally representative.

    “most samples are not nationally representative, although studies have generally sampled to be at least regionally representative.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The direction of causation in the association between weight status and physical activity was not investigated in this analysis.

    “The direction of causation in the association between weight status and physical activity was not investigated in this analysis”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A review of European studies using Actigraph accelerometers reported that 3-5% of children met guidelines using a threshold of >3000 cpm, increasing to up to 87% using a threshold of >2000 cpm.

    “a review of European studies using Actigraph accelerometers reported that 3–5 % of children met guidelines using an accelerometer threshold of >3000 cpm increasing to up to 87 % meeting guidelines using a threshold of >2000 cpm [20].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [20] Guinhouya BC, Samouda H, de Beaufort C. Level of physical activity among children and adolescents in Europe: a review of physical activity assessed objectively by accelerometry. Public Health. 2013;127(4):301–11. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    In analyses comparing activity levels between countries, analyses were restricted to children 9-10 or 12-13, resulting in a sample of 10,741 participants from ten studies in eight countries.

    “In analyses comparing activity levels between countries, we restricted our analyses to children 9–10 or 12–13, resulting in a sample of 10,741 participants from ten studies in eight countries.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A systematic review and pooled analysis concluded that physical activity declined by approximately 7% per year after age ten.

    “A systematic review and pooled analysis [10] concluded that physical activity declined by approximately 7 % per year after the age of ten.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Dumith SC, Gigante DP, Domingues MR, HW K l. Physical activity change during adolescence: a systematic review and pooled analysis. Int J Epidemiol. 2011;40:685–98. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    All analyses were adjusted for the ICAD study from which the data was drawn and for time of year.

    “All analyses were adjusted for the ICAD study from which the data was drawn and also for time of year (May-October vs. November-April, with the months inverted for the three studies from the Southern hemisphere).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    The study had a substantial sample of young people across a wide age range, a consistent measurement instrument and data reduction procedures, and physical activity data from a wide variety of countries.

    “Strengths of this study include a substantial sample of young people across a wide age range, a consistent measurement instrument and data reduction procedures, and physical activity data from a wide variety of countries.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The consistent differences by age and sex persist even though countries differ in total physical activity levels, suggesting that these differences may to an extent be biological.

    “The consistent differences by age and sex persist even though the countries differ in total physical activity levels, suggesting that these differences may to an extent be biological.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    The ICAD provides accelerometer data from a substantial sample of youth reduced using a standard methodology.

    “The ICAD begins to address this issue by providing accelerometer data from a substantial sample of youth reduced using a standard methodology.”
    • Also stated in: § Conclusions · plain
      “The ICAD provides a large volume of accelerometer data reduced using a common protocol, which allows comparison of study samples from a number of countries.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    All countries were alike in showing the same differences in physical activity by sex, by age and (almost always) by weight status.

    “Nevertheless, all countries were alike in showing the same differences in physical activity by sex, by age and (almost always) by weight status.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Robust standard errors were used to adjust for clustering of measurement waves within participants in cross-sectional analyses.

    “When performing cross-sectional analyses, robust standard errors were used to adjust for the clustering of measurement waves within participants.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    Waist-worn accelerometers poorly record upper body physical activity and physical activity when cycling, so in countries with high cycling prevalence physical activity may be underestimated.

    “When worn on the waist, as in the studies comprising the ICAD, they poorly record upper body physical activity and physical activity when cycling [34]. Thus, in countries with a high prevalence of cycling for transportation (e.g. Denmark), physical activity may be under-estimated.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Corder K, Brage S, Ekelund U. Accelerometers and pedometers: methodology and clinical application. Curr Opin Clin Nutr Metab Care. 2007;10:597–603. source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation

    The accelerometer thresholds used to define MVPA have been shown to provide valid estimates for youth aged 5 years and above, but perform poorly for MVPA in children aged 4-6 years and have not been validated in children under 4 years.

    “Whilst the thresholds used have been shown to provide valid estimates of physical activity intensity for youth aged 5 years and above [36], more recently they have been shown to perform poorly for MVPA in children aged 4–6 years [37] and have not been validated in children under 4 years.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [36] Trost SG, Loprinzi PD, Moore R, Pfeiffer KA. Comparison of accelerometer cut points for predicting activity intensity in youth. Med Sci Sports Exerc. 2011;43(7):1360–8. source

      Not checked in the free run.

    • cites [37] Janssen X, Cliff DP, Reilly JJ, Hinkley T, Jones RA, Batterham M, et al. Predictive validity and classification accuracy of Actigraph energy expenditure equations and cut-points in young children. PLoS ONE. 2013;8(11):e79124. 10.1371/journal.pone.0079124. source

      Not checked in the free run.

25 of 25

  • The paper relies on this without support.

    No prior child and adolescent physical activity data pooling study had incorporated samples from such a diverse range of countries using consistent measures and methodology.

    “No child and adolescent physical activity data pooling studies have incorporated samples from such a diverse range of countries using consistent measures and methodology.”
1 of 1

Claims other papers make about this one

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Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting ages for when weight-status differences appear

    Minor

    The results say overweight/obesity was not associated with total physical activity at ages 2-6 and that differences appeared from age seven onwards. The discussion instead says differences were seen from age six.

  • Overweight/obesity prevalence is defined using an obesity threshold

    Minor

    The stated 26% prevalence is consistent with the table's combined overweight and obese categories, not with its 7% obese category. Defining the combined prevalence using a BMI equivalent to >30 kg/m2 conflicts with that distinction.

2 of 2

Cites

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2 of the 39 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. WHO. Global recommendations on physical activity for health. Geneva: World Health Organisation; 2010.

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Related

Authors
Cooper, A. R., Goodman, A., Page, A. S., Sherar, L. B., Esliger, D. W., van Sluijs, E. M., Andersen, L. B., Anderssen, S., Cardon, G., Davey, R., Froberg, K., Hallal, P., Janz, K. F., Kordas, K., Kreimler, S., Pate, R. R., Puder, J. J., Reilly, J. J., Salmon, J., Sardinha, L. B., Timperio, A., & Ekelund, U.
Affiliations
  • National Institute for Health and Care Research (GB)
  • London School of Hygiene & Tropical Medicine (GB)
  • University of Bristol (GB)
  • Loughborough University (GB)
  • University of Southern Denmark (DK)
  • Norwegian School of Sport Sciences (NO)
  • Ghent University (BE)
  • University of Canberra (AU)
  • Universidade Federal de Pelotas (BR)
  • University of Iowa (US)
  • University of Zurich (CH)
  • Centre Hospitalier Universitaire Vaudois (CH)
  • University of Strathclyde (GB)
  • Deakin University (AU)
Corresponding author
Cooper, Ashley R.
ORCID
Venue
International Journal of Behavioral Nutrition and Physical Activity
Publisher
Springer Science and Business Media LLC
Published
2015-09-17
Volume
12
Issue
1
Pages
113-113
ISSN
1479-5868 (ISSN-L)
DOI
10.1186/s12966-015-0274-5
PMC
PMC4574095
OpenAlex
W2143709617
Semantic Scholar
ae7064ed7f3723aad9b0f8279bcd885e364dee03
Cited by
828
References
39
Citations by year
2026: 28 · 2025: 55 · 2024: 79 · 2023: 86 · 2022: 91 · 2021: 106 · 2020: 119 · 2019: 108 · 2018: 71 · 2017: 51 · 2016: 31 · 2015: 1
FWCI
37.83
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • International Journal of Behavioral Nutrition and Physical Activity (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Bristol Research (University of Bristol) (publishedVersion, cc-by)
  • University of Southern Denmark Research Portal (University of Southern Denmark) (publishedVersion, cc-by)
  • SERVAL (Université de Lausanne) (publishedVersion, other-oa)
  • Strathprints: The University of Strathclyde institutional repository (University of Strathclyde) (acceptedVersion)
  • LSHTM Research Online (London School of Hygiene and Tropical Medicine) (acceptedVersion)
  • Ghent University Academic Bibliography (Ghent University) (submittedVersion, other-oa)
  • IRIS (submittedVersion)
  • University of Canberra Research Portal (submittedVersion, cc-by)
  • Loughborough University Institutional Repository (Loughborough University) (submittedVersion, cc-by)
  • Figshare (submittedVersion)
  • Loughborough University Research Repository (Loughborough University) (submittedVersion, cc-by)
  • NORA - Norwegian Open Research Archives (submittedVersion, other-oa)
  • Explore Bristol Research (submittedVersion, cc-by)
  • Zurich Open Repository and Archive (University of Zurich) (submittedVersion, cc-by)
Funders
Medical Research Council (G0701877)
Topics
  • Health Sciences › Medicine › Physiology › Physical Activity and Health
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Obesity, Physical Activity, Diet
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Context-Aware Activity Recognition Systems
Keywords
physical activity, sedentary behavior, youth, children, adolescents, accelerometer-measured activity, sex differences, age differences, overweight and obesity, cross-national variation, light physical activity
MeSH terms
Adolescent, Body Weight, Child, Child, Preschool, Cross-Sectional Studies, Family, Female, Humans, Male, Motor Activity, Obesity, Time Factors, Databases, Factual, Age Distribution, Sex Distribution, Internationality, Overweight, Sedentary Behavior, Self Report, Accelerometry

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