Test-Retest Reliability of Muscle Strength and Physical Function Tests in 6–9-Year-old Children

ABSTRACT

We aimed to assess the test-retest reliability of five muscle strength and physical function tests in healthy children. Forty-one children (6–9 years) were tested three times 4–10 days apart. The test protocol included maximal isometric leg press, hand grip strength, squat jump, long jump, and a 30-sec sit-to-stand test (STST). When comparing test round 1 with 2 and 2 with 3, we found good-to-excellent retest reliability of leg press (intraclass correlation coefficient, ICC = 0.87 and ICC = 0.94), hand grip (ICC = 0.90 and ICC = 0.94), and long jump (ICC = 0.86 and ICC = 0.87). Initially, there was a moderate reliability of squat jump (ICC = 0.71), which was improved to ICC = 0.82 (round 2–3). Similarly, reliability of STST was improved from low (ICC = 0.63) to moderate reliability (ICC = 0.78). We conclude that leg press, hand grip, squat jump, and long jump tests are reliable measurements of children’s muscle strength and function, even without familiarization. Contrary, STST requires familiarization to ensure adequate reliability.

KEYWORDS:

• Pediatrics
• validation study
• physical testing
• muscle function
• familiarization

Acknowledgments

This work was supported by Arla Food for Health (2018). Arla Food for Health had no role in the study design, data collection, data analyses, data interpretation, or writing of the manuscript. We thank the children for participating in the study, the staff at Rundhøjskolen for practical assistance, as well as Nicolaj Appel, Mikkel Bach Garbrecht, Camilla Søgaard, and Simon Bruhn Bjerg Pedersen for their technical assistance.

Additional information

Funding

This work was supported by the Arla Food for Health.