Ability of very young children to produce reliable isometric force measurements

Pediatr Phys Ther. Winter 2005;17(4):251-7. doi: 10.1097/01.pep.0000186507.74151.78.


Purpose: This study was designed to examine the reliability of measuring isometric muscle force in very young children with a hand-held dynamometer (HHD).

Methods: Forty-five children aged two, three, or four years old and with typical development, were divided into three groups of 15 subjects each. Group 1 included two-year-old children (X age = 32 +/- 2.4 months), group 2 contained three-year-old children (X age = 43 +/- 3.8 months), and group 3 included four-year-old children (X age = 54 +/- 3.7 months). Isometric force for shoulder flexion, elbow flexion, elbow extension, knee flexion, and knee extension were measured with a HHD on two occasions separated by five to nine days. The frequency of challenging child behaviors and extra test trails also were recorded.

Results: Intraclass correlation coefficients (ICCs) (2, 1) for the combined group (n = 45) ranged from 0.90 to 0.95. The ICCs (2, 1) for the two-year-old children ranged from 0.76 to 0.91, for the three-year-old group from 0.85 to 0.92, and for the four-year-old children from 0.54 to 0.94. The frequency of challenging behaviors did not appear to be related to the level of reliability.

Conclusion: Using a HHD and standardized procedures, isometric force of children who are typically developing and as young as two years of age can be measured with fair to excellent reliability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child Behavior
  • Child, Preschool
  • Elbow / physiology
  • Female
  • Humans
  • Isometric Contraction*
  • Knee / physiology
  • Male
  • Muscle, Skeletal
  • Physical Examination / instrumentation*
  • Reproducibility of Results
  • Shoulder / physiology