The purpose of this study was to analyze variations in the accuracy of the moment produced by the elbow flexors during feedback-assisted acquisition of a motor skill. The task consisted of minimizing the error around three criterional levels: 20%, 30%, or 50% of the maximal isokinetic concentric moment of these muscles measured at 90 degrees/sec. Healthy women, aged 22 to 30 years, were divided into three groups (nA = 6, nB = 6, nC = 4) corresponding to the above criteria. They were asked to perform 10 sets of 10 right-elbow flexions per day over a period of three consecutive days. The results indicated a significant difference among the groups mainly in terms of overshooting (Group A) or undershooting (Group C) the criterion. On the other hand, Group B subjects performed optimally as indicated both by a significant convergence to the criterion (30%) and a comparatively small number of repetitions required for achievements. These findings demonstrate the existence of an optimal performance point which is located at about 30% of the maximal isokinetic concentric moment.