Test–retest reliability of a battery of field-based health-related fitness measures for adolescents

TLDR

The study aimed to assess the test‑retest reliability of existing health‑related fitness tests in adolescents. Forty‑eight participants (42 boys, 26 girls, mean age 14.8 yr) completed BIA for body‑fat estimation and muscular‑fitness tests (leg dynamometer, push‑up, sit‑up, wall squat) on two occasions one week apart, and reliability was quantified using ICC, paired t‑tests, and coefficient of variation. While BIA produced highly reliable percent‑body‑fat estimates (ICC ≈ 0.94–0.95), muscular‑fitness tests showed substantial systematic error with CVs ranging 9–26 % in boys and 17–21 % in girls, suggesting a need for extensive familiarization before reliable results can be obtained.

Abstract

The main aim of this study was to determine the test-retest reliability of existing tests of health-related fitness. Participants (mean age 14.8 years, s = 0.4) were 42 boys and 26 girls who completed the study assessments on two occasions separated by one week. The following tests were conducted: bioelectrical impedance analysis (BIA) to calculate percent body fat, leg dynamometer, 90° push-up, 7-stage sit-up, and wall squat tests. Intra-class correlation (ICC), paired samples t-tests, and typical error expressed as a coefficient of variation were calculated. The mean percent body fat intra-class correlation coefficient was similar for boys (ICC = 0.95) and girls (ICC = 0.93), but the mean coefficient of variation was considerably higher for boys than girls (22.2% vs. 12.2%). The boys' coefficients of variation for the tests of muscular fitness ranged from 9.0% for the leg dynamometer test to 26.5% for the timed wall squat test. The girls' coefficients of variation ranged from 17.1% for the sit-up test to 21.4% for the push-up test. Although the BIA machine produced reliable estimates of percent body fat, the tests of muscular fitness resulted in high systematic error, suggesting that these measures may require an extensive familiarization phase before the results can be considered reliable.