In the element of fatigue we find one reason for slow practice in the early stages of instruction, especially in all repeated movements.
In slow practice the time between strokes is sufficient to permit the muscular and chemical readjustment necessary as preparation for the following movement. There is no tetanic
[1] overlap and the elimination of muscular waste-products is complete before the next movement sets in.
The quieter the hand, the more necessary is slow practice in repeated movements of the fingers, if the onset of fatigue is to be retarded.
With children, especially, it is advisable to pause perceptibly between each repetition of finger or hand-stroke, so that the interference of one contraction with the next may be eliminated.
Needless to say, slow practice has also a
psychological value in its effect upon the direction of attention. However, at this point, we are concerned only with the physiological phase.
In rapid repetition, as figures in later chapters will show, the muscular coordination differs from that of slow repetition. The mechanical needs of the two movements are different and to meet these efficiently, the muscular adjustments must differ.
Fatigue and fixation will be shown to be necessary correlates of rapidly repeated movements, and therefore, if postponement of fatigue and relaxation be the pedagogic problem, the reduction of the speed of repetition is a physiological necessity.
Muscular tenseness, which accompanies the feeling of hurry or anxiety, is a modification of the biological fear reflex.