440 
MOVEMENT 
in part what probably happens in the muscles as they are 
again made fit to do work. If the exhausted soldier is given 
a small amount of sugar while on the march, his fatigue is 
lessened. This is because sugar is quickly absorbed and 
is used by the muscles as a source of energy for contrac¬ 
tion. This indicates that food will restore muscles. A 
second factor in relieving fatigue is rest, which gives the 
muscle cells time to recuperate by gradually building up the 
muscle protoplasm, and removing wastes. As the energy 
required for the action of a muscle is mainly in the 
muscle protoplasm, there are changes that take place in it. 
Not all the energy can be used in the contraction of the 
muscle, and what remains is a waste substance that has to be 
removed. The removal of this waste is a large factor in re¬ 
lieving fatigue in muscles. 
352. Physical Training. — We are now in possession of the 
facts that enable us to understand the reason for physical train¬ 
ing and some of the benefits to be derived from it. It is true 
that walking and running are forms of exercise, but they are 
both limited to but a part of the more than 500 muscles of 
our body. Every morning our soldiers and sailors are put 
through the “ setting-up ” exercises. These are similar to 
those that you have in school each day except that there 
are more of them. These exercises aim to give every muscle 
in the body a chance to do its proper work. People unaccus¬ 
tomed to a full set of setting-up exercises find themselves lame 
and sore after the first few times. This is because they ex¬ 
erted muscles that had been unused for a long time and these 
muscles are not so strong as they ought to be. In a short 
time this lameness disappears and the morning exercises 
then give vigor and zest to the body. 
These exercises thus serve to keep the bulk of our body, 
our muscles, in a healthy state. Such a condition has an 
important bearing upon our ability to do good work with 
our brains because the mind works best when the rest of the 
