with ease. The power of coordination is increased, so that a desired end
is attained with the least amount of physical force and nervous energy. In
learning to row, play baseball, ride the bicycle, or in any other
exercises, the beginner makes his movements in a stiff and awkward manner.
He will use and waste more muscular force in playing one game of ball, or
in riding a mile on his wheel, than an expert would in doing ten times the
work. He has not yet learned to balance one set of muscles against their
antagonists.

[Illustration: Fig. 40.--The Standard Special Chest Weight.

A convenient machine by means of which all the muscles of the body may be
easily and pleasantly exercised with sufficient variations in the
movements to relieve it of monotony.

A space 6 ft wide, 6 ft deep, and 7 ft high nearly in front of the machine
is required for exercise.]

In time, however, acts which were first done only with effort and by a
conscious will, become automatic. The will ceases to concern itself. By
what is called reflex action, memory is developed in the spinal cord and
the muscular centers (sec. 273). There is thus a great saving of actual
brain work, and one important cause of fatigue is removed.

83. Effect of Exercise on Important Organs. The importance of
regular exercise is best understood by noting its effects upon the
principal organs of the body. As the action of the heart is increased both
in force and frequency during exercise, the flow of blood throughout the
body is augmented. This results from the force of the muscular
contractions which play their part in pressing the blood in the veins