Pediatrics and Physical Activity

Study Design:
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Quality Rating:
Research Purpose:
To study the influence of applied exercise training in selected obese children on the anthropometric, hemodynamic and anatomic adaptive changes in their cardiovascular system.
Inclusion Criteria:

Obese children 10 and 11 years old at Kitakyushu City Kokura Elementary School; obesity defined as % relative body weight (RBW) greater than 20% (%RBW expressed as excess weight in percent of ideal body weight (IBW) defined as weight for height).

Exclusion Criteria:
None specified
Description of Study Protocol:

Group 1: 8 obese children, 10 years old (2M, 6F), participated in a special exercise program for one year and were compared with 5 normal weight children (1M, 4F) who participated in regular physical education class.

Group 2: 10 obese children, 11 years old (5M, 5F), who had already participated in special exercise program for one year participated in it again for another year and were compared with 10 normal weight children (4M, 6F) who participated in regular physical education class.

Special exercise program consisted of 20 minute jogging session during noon recess and after school, 5 days per week. Objective was to maintain heart rate between 145 and 155 beats per minute after the jogging session.

Obese groups tested for outcome variables before and after 3 and 12 months of program; control children tested before and after 12 months.

Obese children were kept free from caloric and exercise restrictions.

Statistical Analysis

Student’s t test for comparisons before and after the exercise program.

Data Collection Summary:

Dependent Variables

height; weight; size of chest; triceps and subscapula skinfolds (average of two measurements using calipers); %RBW; blood pressure; heart rate; left atrial, aortic, left ventricular end-systolic and end-diastolic dimensions, septal and left ventricular posterior wall thickness (measured using Toshiba SSL-51U with 10mm diameter, 2.25 mHz transducer and repetition frequency 1000 pulses/sec echocardiogram), left ventricular mass (calculation as described by Richard et al.), total voltage of S wave in lead V1 and R wave in lead V5 (SV1 + RV5) (measured using standard 12-lead electrocardiogram).

Independent Variables

Participation in special exercise program vs regular physical education class

Control Variables

None specified

Description of Actual Data Sample:


Original Sample: 18 obese children and 15 control children.


Withdrawals/Drop-Outs: None specified.

Final Sample: 18 obese children and 15 control children.

Location: Kitakyushu City Kokura Elementary School, Japan

Race/Ethnicity: Japanese

SES: not specified

Summary of Results:

Obese children in group 1 (10 years old) had %RBW greater than 20% at baseline.

Obese children in group 2 (11 years) had %RBW of 5% at baseline (after 1 year of exercise).


Group 1: obese children decreased %RBW after 1 year of special exercise program from 43.3 +/- 19.8% to 21.5 +/- 19.5% (p<.001). Weight decreased but was not significant.

%RBW for control children not reported, but weight increased from 32.9 +/-1.7kg to 37.1 +/- 2.9kg (p<.005).

Group 2: obese children increased weight from 45.9 +/-5.9kg to 49.5 +/- 6.4kg (p<.001) and decreased %RBW from 5.0 +/- 6.0 to 3.0 +/- 7.0 (difference not significant).

%RBW not reported for control children, but weight increased from 40.3 +/-7.4 kg to 44.5 +/-6.6kg (p<.001).

Resting heart rate of obese children decreased after 3 months of exercise program, decreased significantly after 1 year.

Left ventricular end-diastolic dimension increased without increase in left ventricular posterior wall thickness after 1 year.

Total voltage in SV1 + RV5 decreased after three months of exercise but returned to pre-training voltage after 1 year.

No change after 2 years of training.

Author Conclusion:

A program of jogging 5 days/week may produce a weight reduction, a decrease of resting heart rate, and an increase in left ventricular end-diastolic dimension.

Effects of exercise on cardiac structure may differ among normal weight children, obese children and adults.

Funding Source:
Hoffman LaRoche (Switzerland)
Pharmaceutical/Dietary Supplement Company:
University/Hospital: Unversity of Lausanna
Reviewer Comments:


  • small study sample
  • no measure of adiposity for control children
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? N/A
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? N/A
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
2. Was the selection of study subjects/patients free from bias? No
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? No
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? No
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? No
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A