356 THE HUMAN MOTOR 



A' A B B' 



FJO. 254, 



Vertical oscillation passes from be to ac 

 when the step is A'B' instead of AB. 



small steps (fig. 254) : (ac instead of be) and it is also desirable 

 in lengthening the step, to bend at the same time, the 

 carrying leg, thus diminishing the radius O'B' and making a 

 nearly rectilineal movement of the hip. De Raoul (*) has a high 

 opinion of the advantage of marching with bent knees. Agri- 

 cultural labourers, and others who desire to spare themselves 

 unnecessary exertion, adopt a similar gait. Furthermore, as 

 Compte and Regnault ( 2 ) found by chronophotographic methods, 

 the vertical oscillations are thereby greatly diminished. On 

 the other hand, the extra flexion of the knee caused by this 

 method of walking, entails additional muscular contraction. 

 Hence, although the practice has much to recommend it, it should 

 be adopted with caution in the case of infantry marching with 

 loads. ( 3 ) 



270. Movements and Oscillations of the Body while Walking. 



The movements which are exhibited in the regular succession of 

 paces in walking are complicated by oscillatory movements 

 of various parts of the body besides the lower limbs. Even the 

 movements of the legs themselves are not exempt from such com- 

 plications. It can easily be seen that the feet, the knees, and the 

 hips oscillate from side to side of their sagittal planes. Thus the 

 foot exerts a lateral pressure on the ground besides the vertical 

 and tangential pressures, and, as will be seen from fig. 253, the 

 action of the two lower limbs is not absolutely symmetrical. 



There would seem to be a real structural difference between 

 the right and the left sides of the body. The fact that the great 

 majority are right-handed may be due to an instinct of protection 

 in regard to the heart. ( 4 ) 



( x ) Count de Raoul (Revue de I'Infanterie, 15th August, 1896) ; Raoul 

 and Regnault, Comment on Marche, 1897. 



( 2 ) Comte and Regnault (Arch, de Physiol., 1896, p. 180) ; A. Schmidt, 

 Unser Korper, p. 426, 1899. 



( 8 ) See the criticisms by Paul Richer in the Tvaiie de Physique Biologique, 

 by Marey, d'Arsonval, etc., vol. i., p. 216, 1901, and Regnault's reply in 

 Journ. de Physiol., 1913, p. 49. 



( 4 ) Aristotle had already made this distinction ; see also Guldberg, 

 Etudes sur la Dissymetrie chez I'Homme, Christiania, 1897. Chauffard 

 (Acad. de Med., 12th November, 1912) 



