The strength required for motor activities should be exerted effectively according to the type of activity and the load size. This study examined the relationship between the accuracy of handgrip exertion for demanded forces of 20%–80% of the maximal voluntary contraction (MVC) and laterality. Subjects were 100 healthy young males (mean age, 22.4 ± 2.8 years). After the handgrip MVC was measured, subjects attempted to exert a handgrip at demanded forces of 20, 40, 60, and 80% of the MVC. All tests were performed twice and with dominant and non-dominant hands, and mean values were used for statistical analysis. Differences between demanded forces and exerted forces were converted into relative values based on each subject’s MVC. Two-way repeated measures ANOVA showed significant interaction between demanded forces and laterality. In multiple comparison tests, smaller demanded forces were associated with larger errors only in the non-dominant hand. For demanded forces of 20% and 40% MVC errors were smaller for the dominant hand than for the non-dominant hand. The non-dominant hand is used less than the dominant hand in daily life and in sport activities. It is therefore not unexpected that a laterality-based difference in the accuracy of exerted force for each demanded force is found, and the accuracy of exerted force at low demanded forces was inferior for the non-dominant hand. In conclusion, there was a difference in the accuracy of exerted force for each demanded force for the non-dominant hand with a larger error at lower demanded forces. In particular, the accuracy of exerted force in response to demanded forces of 40% MVC or less was inferior in the non-dominant hand compared with that in the dominant hand. Laterality is therefore a significant factor in force response to lower demanded force values.
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