title: Ability of very young children to produce reliable isometric force measurements.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: School of Physical Therapy and Rehabilitation Science, University of Montana, Missoula, MT 59812, USA. carrie.gajdosik@umontana.edu
authors.forename: Carrie Giller
authors.initials: CG
authors.lastname: Gajdosik
mesh_terms: D002652:Child Behavior; D002675:Child, Preschool; D004550:Elbow / Q000502:physiology; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007717:Knee / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal; D010808:Physical Examination / Q000295:instrumentation*; D015203:Reproducibility of Results; D012782:Shoulder / Q000502:physiology