LOCOMOTION 351 



The motions of walking have been specially studied by the 

 brothers Weber, by Marey, and by Braune and Fischer, f 1 ) 

 We shall draw most extensively on the two latter authorities, 

 since, while fully utilizing Marey 's results, they extended and 

 completed his work. The technique of the subject has laid under 

 contribution both graphic and chronophotographic methods. By 

 these we can determine the relations between the length of the 

 step, the pressure of the foot on the ground, the muscular effort 

 exerted, the nature of the movement, and the speed. 



The act of walking is essentially a disturbance of the mechani- 

 cal equilibrium of the body, producing displacement of the legs, 

 which alternately sustain the total weight of the body. This 

 transference of weight is achieved by a regular oscillation of the 

 general centre of gravity, which is always brought to a position 

 above the leg which is on the ground the " carrying " leg 

 while the other leg, the ''oscillating " leg, leaves the ground with 

 the point of its foot, swings forward and replaces itself on the 

 ground in advance of the other leg. A " pace " is the distance 

 between the centres of the feet when walking. The " double 

 pace " is the complete cycle after which the legs and feet are in 

 the same relative positions as before. 



The double pace has three phases (A.B and C, in fig. 249). The 

 first occupies about T % of a second during which time the hinder 

 leg leaves the ground by the toe, and swings forward, meeting the 

 ground again with the heel. A period of about ^ of a second 

 then elapses during which both feet are on the ground. There 

 is therefore firstly a period of oscillation and secondly a period 

 of " double support." In ordinary walking (121 paces, 0-75 m. 

 long per minute), the time of a double pace is about one 

 second. 



Hence the " oscillating " leg rests on the ground for T % of a 

 second, acting as a support for the body. Propulsion is attained 

 by the progressive shifting of the point of contact with the ground 

 from the heel to the toe. Fig. 250 exhibits the successive move- 

 ments in a double pace. 



Fischer ( 2 ) analysed the double pace. He took as his 

 subject an adult weighing 58-7 kg. and 1-87 metres in height, the 

 length of his lower limbs being 0-87 m. The average number of 

 double paces per minute was 121 and the average length of pace 



( x ) E. and W. Weber, Mecanique de la Locomotion chez I'Homme, trans. 

 Jourdan, 1843 (a poor translation) ; Marey, Le Mouvement, Paris, 1894 ; 

 Engl. tr., London, 1894); Braune and Fischer (Abhandlungen, vol. xx ., 

 No. 4 ; xxv., No. 1 ; xxvi., Nos. 3 and'7; xxviii., Nos. 5 and 7; Der Gang 

 d. Menschen, 1895 to 1904; about 700 quarto pages). 



( 2 ) O. Fischer (loc. cit., vol. xxv., No. 1), Examining 103 soldiers of the 8th 

 Regiment (in Saxony) he found that the size of the step is variable and 

 reaches at least 0.80 m. (loc. cit., vol. xxviii., No. 5, p. 343, 1903). 



