Measuring handgrip strength in school children: inter-instrument reliability between Takei and Jamar

The aim of this study was to determine inter-instrument reliability between Takei and Jamar dynamometers in school children. Fifty-six five grade participants aged eleven to twelve (n = 32 boys, n = 24 girls) performed handgrip strength test on two different occasions, with a 5-day gap between them, as test-retest. The Pearson correlation coefficient showed very large to almost perfect correlation between both devices (r = 0.76-0.91) which was graphically confirmed by Bland-Altman method. Test-retest also showed high reliability (ICC = 0.78-0.85) for Jamar and Takei. Trivial, nonsignificant differences (p > 0.05) were observed between for test-retest trials for Takei left hand (ES = 0.04), right hand (ES = 0.12) and Jamar left hand (ES = 0.15). According to the results, both the Jamar and Takei dynamometers are valid and reliable for measuring schoolchildren, and both devices may be used to assess a student's handgrip strength for this age group.