Cued and non-cued repetitive ballistic movements. A kinematic study in healthy subjects

Repetitive ballistic movements of the upper limbs were registered in 63 healthy subjects with an optoelectric 3-dimensional infrared computerized system. For evaluation of externally cued movements the arm was moved at maximum speed between two targets. As internally cued movements elbow flexion and extension at maximum speed was performed. At non-cued movements the subject shifted the hand between pronation and supination as fast as possible without further instructions. Movement velocity decreased progressively with increasing age at an annual rate of 0.5-0.6%. Women moved more slowly than men during cued movements, whereas no sex differences were found for non-cued movements. The peak velocity of cued movements remained unchanged during the 20 s performance period, whereas non-cued movements showed signs of fatigue with slowing. In conclusion, the maintenance of velocity during simple repetitive ballistic movements in healthy subjects depends on cueing and on sensory-motor function rather than on cognitive motor processing.