HUMAN MOVEMENTS 145 



the diagram to the movements of the extremities in 

 question. Fig. 98 shows the movements of a leg in 

 running. The sets of dotted lines show at any par- 

 ticular moment the angle formed by each segment with 

 the vertical, as well as the path followed by each joint. 

 In geometrical photographs, thanks to the great 

 number of the images, the discontinuity of the phases 

 almost entirely disappears, and the actual path followed 

 by each part of the body can be seen represented 

 almost as a continuous curve. These indications are 

 most useful in studying movement from the point of 

 view of dynamics, for by them the velocity as well as 

 the acceleration of the body mass can be measured. 



