THE EXERCISE WE NEED 169 



when similarly used. No muscle can help growing 

 bigger and stronger if it is used ; whereas, if it is not 

 used, it is just as sure to grow smaller and weaker. 



Another point about exercise is that it increases one's 

 appetite and one's digestion of food. This is accom- 

 plished very slowly, but a person who is working or 

 who is out of doors a great deal will need more food 

 than one who sits still most of the time. 



The man who wishes to succeed in those athletic 

 sports which depend on strength, quickness, or endur- 

 ance trains for it ; that is, he uses exercises which increase 

 the circulation of his blood and which make the muscles 

 harder, larger, stronger, and quicker in their movements, 

 for these exercises make a man more healthy in every way. 



Not only this, but the more he practices, the better 

 can he do each particular thing, for muscles learn les- 

 sons as truly as children learn them. 



Perhaps the most important reason for having gym- 

 nastics in school is that the body may learn to hold 

 itself in the correct position and thus prevent curvature 

 of the spine. This curvature often comes from bending 

 over school desks so much of the time. 



You will notice that your school gymnastics give 

 more work to the big muscles of the back and the neck 

 than to the smaller muscles of the arms. The reason is 

 that the back must be straightened, and the exercises are 

 to keep the muscles strong enough to hold the backbone 



