Exercise as it relates to Disease/Determinants of physical activity in obese and non-obese children

What is the background to this research?Edit

  • US children and adolescents had shown an increase in prevalence of obesity at an alarming rate in this study. Between the 10 years of the second (1976–1980) and third (1988-1991) administration of the National Health and Nutrition Examination Survey (NHANES), the prevalence of obesity among children aged 6–11 years and adolescents aged 12–17 years (based on age- and gender-specific 95th percentile body mass index (BMI) cut-off points) increased from 6 to 10.7% and 4.8 to 10.7%.[1]

  • Reports at the time had confirmed similar increases in the prevalence of obesity among pre-schoolers and infants.[2] This rising trend had also been linked to represent a critical public health problem

  • Obese children and adolescents were found to be more at risk for adult obesity [3] and were more likely than their counterparts to experience significant short-term health problems such as hyperlipidaemia, hypertension, glucose intolerance and orthopaedic complications.[4]

  • The adverse social consequences of childhood and adolescent obesity may have long-lasting negative effects on self-esteem, body image and economic mobility.[5] Thus, presenting a real-world issue caused by obesity in children.

Where is the research from?Edit

  • The research was approved by the University of South Carolina Institutional Review Board and was published on the July 6, 2001 in the International Journal of Obesity.

What kind of research was this?Edit

  • The research was a cross-sectional study aimed to compare PA patterns and the hypothesized psychosocial and environmental determinants of PA in an ethnically diverse sample of obese and non-obese middle school children.

What did the research involve?Edit

  • The research involved one-hundred and thirty-three non-obese and fifty-four obese sixth grade children with a mean age of 11.4 +/- 0.6.

  • Obesity status was determined using the age-, race- and gender-specific 95th percentile for BMI from NHANES – 1.

  • Objective measurements were collected of PA over a 7-day period using the Computer Science and Applications Inc. (CSA) 7164 accelerometer: total daily counts; daily moderate (3–5.9 METs) physical activity (MPA); daily vigorous physical activity (≥6 METs; VPA); and weekly number of 5, 10 and 20 min bouts of moderate-to-vigorous physical activity (≥3 METs, MVPA).

  • Self-report measures were collected of PA self-efficacy; social influences regarding PA, beliefs about PA outcomes; perceived PA levels of parents and peers, access to sporting and/or fitness equipment at home, involvement in community-based PA organizations; participation in community sports teams; and hours spent watching television or playing video games.

What were the basic results?Edit

  • Compared to their non-obese counterparts, obese children exhibited significantly lower daily accumulations of total counts, MPA and VPA as well as significantly fewer 5, 10- and 20-min bouts of MVPA.

  • Obese children reported significantly lower levels of PA self-efficacy, were involved in significantly fewer community organizations promoting PA and were significantly less likely to report their father or male guardian as physically active


  • S.G. Trost, L.M Kerr, D.S. Ward, R.R. Pate all contribute to the makings of this research. Trost, from the School of Human Movement Studies, The University of Queensland assessed the validity and inter-instrument reliability of the CSA 7164 activity monitor in children aged 10–14.

  • The main authors Kerr and Pate from the Department of Exercise Science, School of Public Health, University of South Carolina, and Ward from the School of Public Health, University of North Carolina at Chapel Hill. Trost, Ward, and Pate are all highly regarded individuals at their respective schools, nationally, and internationally with each having multiple accounts of published work. In researching, there was little information found on Kerr and cannot comment on their reputation/background.

  • The subjects for this study were 187 sixth grade students from four randomly selected middle schools in Columbia, South Carolina. Disadvantages of random selection include the time needed to gather the full list of the population, retrieving and contacting the list via the schools, and bias that could occur when the sample set is not large enough to adequately represent the full population.[6]

  • The objective of the article was to compare in an “ethnically diverse sample”, however, in the methodology, only seem to state male and female African Americans rather than any other ethnicities such as Chinese American or Latin American etc.

  • The authors findings can be found appropriate due to the objective nature of their measurements using instruments such as the CSA 7164 activity monitors.

  • Non-monitored activities were given PA scores and were calculated with and without the inclusion of self-reported participation in swimming, cycling and weight training. Inclusion of these data resulted in no changes to the mean MPA and VPA scores and were not included in the analyses.

  • The nature of this study precluded from inferring a causal relationship between PA and obesity status. Thus, the lower activity profile exhibited by the obese children relative to their counterparts may have been the consequence of obesity and not the cause of it.

  • Although alarming to find that approximately 30% of the sixth-grade sample could be classified as obese, the modest sample size of the obese group precluded their ability to conduct sex-specific analyses.

  • Due to logistic concerns, the study included a relatively small number of determinant variables and did not collect direct data from parents. Therefore, future studies should expand the list of determinants to include physical self-perception variables such as social physique anxiety and body attractiveness; and more comprehensive measures of parental and peer support/ encouragement for physical activity.

What conclusions can we take from this research?Edit

  • The results are consistent with the hypothesis that physical inactivity is an important contributing factor in the maintenance of childhood obesity.

  • Interventions to promote PA in obese children should endeavour to boost self-efficacy perceptions regarding exercise, increase awareness of, and access to, community PA outlets, and increase parental modelling of PA

  • Considering the critique, it is believed a different sampling technique should be undertaken, including multiple ethnicities and have all PA monitored rather than relying on some aspects of self-reporting.

Practical adviceEdit

  • Given the study findings and the critique multiple considerations can be made for sound practical advice. Advice such as using a different selection process to increase efficiency, inclusion of more ethnicities to adhere to the objectives, calculating all PA into the analyses rather than factoring into only MPA, VPA and MVPA and not relying on self-report figures to do so. Having sex-specific figures as a separate study to incorporate into the data, and finally, increase logistic parameters to be able to collect more data from direct sources.

Further information/resourcesEdit





  1. (1)
  2. (2,3)
  3. (4)
  4. (5,6)
  5. (6,7)
  6. (8)
  1. Troiano RP, Flegal KM. Overweight children, and adolescents: description, epidemiology, and demographics Paediatrics 1998 101: 497–504.
  2. Ogden CL, Troiano RP, Briefel RR, Kuczmarski, Flegal KM, Johnson CL. Prevalence of overweight among preschool children in the United States, 1971 through 1994 Paediatrics 1997 99: E1.
  3. Mei Z, Scanlon KS, Grummer-Strawn LM, Freedman DS, Yip R, Trowbridge FL. Increasing prevalence of overweight among US low-income preschool children. The Centres for Disease Control and Prevention Paediatric Nutrition Surveillance, 1983 to 1995 Paediatrics 1998 101: E12.
  4. Whitaker RC, Wright JA, Pepe MS, Seidel KD, Dietz WH. Predicting obesity in young adulthood from childhood and parental obesity New Engl J Med 1997 337: 869–873.
  5. Must A, Strauss RS. Risks and consequences of childhood and adolescent obesity Int J Obes Relat Metab Disord 1999 23 (Suppl 2): S2–S11.
  6. Dietz WH. Health consequences of obesity in youth: childhood predictors of adult disease Paediatrics 1998 101: 518–525.
  7. Neumark-Sztainer D. The weight dilemma: a range of philosophical perspectives Int J Obes Relat Metab Disord 1999 23 (Suppl 2): S31–S37.
  8. Jawale KV. Methods of Sampling Design in the Legal Research: Advantages and Disadvantages [Internet]. citeseerx.ist.psu.edu. 2012. Available from: https://citeseerx.ist.psu.edu/viewdoc/download?doi=

Figure 1. Movement counts and estimated daily participation in moderate and vigorous physical activity in 133 non-obese and 54 obese children. Figure 2. Weekly frequency of objectively measured 5, 10-and-20 min bouts of MVPA in 133 non-obese and 54 obese children.