Knee position error detection in closed and open kinetic chain tasks during concurrent cognitive distraction.

It is important to establish whether presumed differences among varieties of motor responses are manifested in related differences in performance. In order to determine possible functional distinctions between closed and open kinetic chain tasks, participants' performance in the presence or absence of cognitive distraction on an error-detection task was assessed. Individual testing of participants consisted of knee extension and flexion movements to experimenter-defined positions, approximating the 25th, 50th, and 75th percentile of the participants' range of motion on the apparatus. Performance under conditions of distraction was significantly worse than in the absence of distraction. Performance using longer movements was significantly more accurate. No substantial differences were found between closed and open kinetic chain movements. Limitations of this research for the distinction between open and closed chain tasks are addressed, and clinical implications of the effects of distraction are presented.