OBJECTIVE: Muscle strength training is one of the most common therapy methods in physical therapy programs, and the usual goal of this treatment is to improve muscle strength. Little attention has been paid, however, to the effects of strength training on the other components of motor performance. This study examined the effects of a 10-week strength training program on the motor performance of the hand, including reaction time, speed of movement, tapping speed, and coordination in normal healthy volunteers. DESIGN: Before-after trial. SUBJECTS AND SETTING: Sixteen healthy women volunteers aged 25 to 45 years participated. INTERVENTION: Subjects accomplished a 10-week muscle strength training program of the upper extremities. MAIN OUTCOME MEASURES: Reaction time, speed of movement, tapping speed, and coordination were measured three times on consecutive days, and muscle strength and electromyographic values of the right upper extremity were recorded once before the training period. After the training period, the same measurements were made as before the training. RESULTS: The 10-week strength training decreased choice reaction time by 6% (p