Control of multijoint drawing movements: a comparison of young and elderly adults

Nine young adults and 11 older adults drew repeatedly a circle and ellipses oriented in four directions using shoulder and elbow joint movements. The varying orientations of the ellipses were configured to stress different joint combinations and in turn alter the joint torques generated in each condition. Each template was traced at increasing levels of cycling frequency both with and without vision. Distortions of movement trajectories occurred for both groups at high cycling frequencies, however the pattern of distortion as well as control and coordination of joints differed between groups. Elderly adults showed a preference towards maintaining the shape of the trajectory trading off speed and slope of the trajectory.