RUNNING AND LEAPING. 153 



prolonged very fast walking. From the fact that each 

 foot reaches the ground heel first, but leaves it toe last, the 

 length of each stride is increased by the length of the foot. 



Running. In this mode of progression there is a mo- 

 ment in each step when both feet are off the ground, the 

 Body being unsupported in the air. The toes alone come in 

 contact with the ground at each step, and the knee-joint 

 is not straight when the foot reaches the ground. When 

 the rear foot is to leave the support, the knee is suddenly 

 straightened, and at the same time the ankle-joint is ex- 

 tended so as to push the toes forcibly on the ground and 

 give the whole Body a powerful push forwards and upwards. 

 Immediately after this the knee is greatly flexed and the 

 foot raised from the ground, and this occurs before the 

 toes of the forward foot reach the latter. The swinging 

 leg in each step is violently pulled forwards and not suf- 

 fered to swing naturally as in walking. By this the rapid- 

 ity of the succession of steps is increased, and at the same 

 time the stride is made greater by the sort of one-legged 

 leap that occurs through the jerk given by the straighten- 

 ing of the knee of the rear leg just before it leaves the 

 ground. 



Leaping. In this mode of progression the Body is 

 raised completely from the ground for a considerable 

 period. In a powerful leap the ankles, knees, and hip- 

 joints are all flexed as a preparatory measure, so that the 

 Body assumes a crouching attitude. The heels, next, are 

 raised from the ground and the Body balanced on the toes. 

 The centre of gravity of the Body is then thrown forwards, 

 and simultaneously the flexed joints are straightened, and 

 by the resistance of the ground, the Body receives a propul- 

 sion forwards; much in the same way as a ball rebounds 

 from a wall. The arms are at the same time swung for- 

 wards. In leaping back, the Body and arms are inclined in 

 that direction; and in jumping vertically there is no lean- 

 ing either way and the arms are kept by the sides. 



