124 PHYSIOLOGY CHAP. 



of the shoulders are less marked in running than in walking. On 

 the other hand the inclination of the trunk forward in the first 

 period of the contact, and backward in the second half, is much 

 more pronounced in running. 



The speed of running, according to the statement of the 

 Webers, may exceed 4'5 m. per second; anything beyond these 

 limits can only be kept up for a short distance. 



Galloping differs from walking and running, in which there is 

 a regular alternation of the movements of the limbs on the two 

 sides, which are placed on the ground at regular intervals. 

 Galloping deserves a short mention, although it is not a normal 

 form of locomotion in man. According as the gallop to the 

 right or to the left is imitated, the right or left foot is put forward 

 at each step, like a galloping horse. In Fig. 83, which represents 



Fio. 83. Tracing of galloping to the right. (After Marey.) D, movements of right foot ; 

 S, of left foot ; 0, vertical oscillations. 



a tracing obtained by Marey with recording shoes, four phases can 

 be distinguished in the gallop. The left foot, the more posterior, 

 first touches the ground with a firm and prolonged pressure ; 

 while the left foot is still on the ground the right foot is placed in 

 a more advanced position (double contact), but with less and 

 shorter pressure ; the second contact is at once followed by 

 elevation of the left foot (simple contact) ; and finally comes the 

 rise of the right foot also (suspension), which lasts a perceptible time 

 before the tap of the left foot begins the second cycle. Line of 

 the figure shows that the two taps are followed by two slight 

 elevations of the head, followed in turn by two depressions, most 

 of which coincide with the phase .in which the whole body is 

 unsupported in the air. 



Jumping consists essentially in the rapid and energetic 

 extension of one or both lower limbs, preceded by a pronounced 

 flexion, by which means the body is thrown upward and forward. 

 The mechanism of jumping varies considerably according to its 

 purpose. 



Chronophotographs on a fixed plate of the successive positions 

 of an individual who is jumping over a hedge or ditch (Fig. 84) 

 show that during the spring and the upward and forward thrust 



