A clinical measurement study.To test the applicability of Fitts' paradigm to grasping tasks in individuals with chronic stroke.Fitts' Law relates the time of target achievement to task difficulty in repetitive motor tasks.Six male chronic stroke patients performed repetitive actuation of a grip force dynamometer with their affected hands for 12 sessions over four to six weeks.Movement times followed Fitts' behavior with correlations of R2>0.8 for all subjects. Grasp control improved during training, as indicated by an average decrease in Fitts' slope of 26% at high difficulty levels (p<0.05), and decreases in the number of force corrections and in jerkiness, both at p<0.001 level.The Fitts' grip force targeting protocol provides an objective standardized instrument for grasp proficiency quantification and a potentially efficacious platform for hand training for persons with stroke.N/A.