Neuronal control of ballistic finger movements in man: task specific electromyographic patterns.
The electromyographic (EMG) patterns of finger flexor and extensor muscles have been studied during ballistic finger movements in three different conditions: (1) rapid isotonic finger flexion; (2) throwing and (3) catching a tennis ball. In 1 and 2 a three-burst pattern was observed. In the latter, the first agonist burst was shorter and of higher amplitude compared to condition 1. Catching a ball was connected with a coactivation of extensor and flexor muscles prior to and during ball contact and a contribution of segmental stretch reflexes to the flexor activation. The finger flexion movement was 10-15 times faster than in conditions 1 and 2. After ischaemic blocking of group I afferents and in patients with rigidity, a short inhibition of the increased extensor activation became predominant and was the basic mechanism underlying finger flexion for catching a ball. It is concluded that in natural ballistic finger movements, other neuronal mechanisms are of functional significance than those seen in the usual experimental paradigms.
D001696:Biomechanical Phenomena; D004576:Electromyography; D005385:Fingers; D006801:Humans; D009043:Motor Activity / Q000502:physiology*; D009068:Movement; D009132:Muscles / Q000502:physiology*; D009424:Nervous System Physiological Phenomena; D010300:Parkinson Disease / Q000503:physiopathology