Relationships between grip strength, dexterity, and fine hand use are attenuated by age in children 3 to 13 years-of-age.

[Purpose] The purpose of this secondary analysis of data from the validation phase of National Institutes of Health Toolbox study was to describe the relationship between grip strength, dexterity, fine hand use, and age. [Participants and Methods] Children 3 to 13 years (n=132) contributed data. Grip strength was measured bilaterally with a Jamar dynamometer. Dexterity was measured bilaterally with the Nine-hole Peg Test. Fine hand use was characterized using 5 items of the Bruininks Oseretsky Test of Motor Proficiency. [Results] All grip strength and dexterity and fine hand use measures were correlated moderately to highly with one another and with age. The Cronbach's alpha for all measures was 0.88. Factor analysis suggested that all measures loaded strongly on a single component with the first factor explaining 75.6% of the total variance. Nevertheless, correlations between grip strength and dexterity and fine hand use measures were mostly negligible after controlling for age. [Conclusion] As moderate to strong relationships between grip strength and dexterity and fine hand use are attenuated by age in children of 3 to 13 years, we cannot recommend the use of any one measure over others to characterize motor function of the hand.