August 15, 1901] 



NA TURE 



Z77 



PHOTOGRAPHIC ANALYSIS OF THE 

 MOVEMENTS OF ATHLETES} 



TV/r MAREY has again applied his chronophotographic 

 -'■'-'■ • methods in making an analysis of the movements 

 of athletes while exercising their strength in different 

 \yays. His delightful experiments, which have been but 

 little repeated by others, are described in detail in " Le 

 Mouvement " (par E. Marey. Paris: 1894. Translated 

 into English by E. Pritchard. London : Heinemann, 



o 



-Composite pictu 



1895). The methods are, for the most part, so simple, 

 and the results so valuable, that they should prove 

 themselves attractive to the student of those subjects in 

 which movement of any kind is to be measured. In igoo, 

 during the exhibition in Paris, there was a large gymnastic 

 meeting and athletic sports. The administration of the 

 exhibition nominated a commission of physiology and 

 hygiene, for the purpose of following the meetings 

 and gathering from that unique assembly of the best 



The chronophotographic method gives a series of instan- 

 taneous photographs, on a long ribbon which is un- 

 wound ; the number of pictures varies from fifteen to 

 twenty or more per second. By this means the phases 

 of a movement are perfectly represented. Figures so 

 produced on a band being somewhat difficult to compare 

 with one another, it was found to be more convenient to 

 arrange them, as in P"ig. 3, in three columns, the succes- 

 sion of pictures in each column reading from top to bottom, 

 commencing on the left. The subject is that of " putting 

 the weight " by the American athlete, Sheldon. 

 The weight used by all competitors was 

 7'25 kilogrammes, = i5'95 lb., or the 16 lb. 

 shot used in English athletic sports, and the 

 distance covered was 1402m. = 45'98 feet. 

 Fig. 3 shows the athlete at the moment of 

 his take-off from the right leg. At the end 

 of his jump, and at the moment when the 

 left foot touches the ground, he brings his 

 right arm into action, which moves the shot 

 upwards and forwards, giving it the greatest 

 velocity possible. 



The competitor is allowed a run of 2m., 

 and he stands in a square traced on the 

 ground, the boundary of which he must not 

 pass. In order that the velocity of the 

 different movements of the athlete may be 

 estimated, it is necessary to introduce into 

 the pictures the representation of both time 

 and space. The time is measured by means 

 of a chronograph (visible only in the five 

 last pictures) ; it consists of a black dial 

 furnished with divisions, over which a white 

 pointer moves ; the pointer makes one revo- 

 lution in one second. The angular space swept out 

 by the needle between two successive pictures indicates 

 the time which has elapsed. An easy way of measuring 

 these intervals is to determine the number of images 

 contained in one, a half or quarter revolution of the 

 needle. In Fig. 3, the last five pictures were made 

 in one quarter of a revolution of the pointer, or at the 

 rate of twenty pictures per second, so that between 

 two successive images the displacement (which is 



— Composite picture of long jump by Su-eeney. 



athletes in the world the infoimation which it afforded. 

 Its object was to determine, from a physiological point 

 of view, the action of the various forms of exertion on the 

 organic functions, viz. ihe respiration, the circulation of 

 the blood, the digestion and, finally, the general health. 

 The commission also studied different kinds of sports 

 with a view to understand their mechanical details and 

 discover the secret of the superiority of certain athletes, j 



1 The accompanying ilkistralions are from La yatiiri, 



NO. 1659, VOL. 64] 



estimated for any point on the body) is made in i/20th 

 second, and it is the same for the displacement of the 

 weight. The true extent of displacement is finally deter- 

 mined by placing a divided metric scale on the ground ; 

 this rule is photographed at the same instant as each 

 new position of the athlete, and it serves as a scale whereby 

 the path traced out by each point under consideration 

 may be computed — M. Marey gives the following tncthoa 

 of comparing images by superposition. 



