Ziad Joseph Rahal
|Figure 1. The
arthrodynamometer. (Amar, 1915, p. 833)
Jules Amar (1879–1935) may not be well known in medical texts, but his work helped initiate two important scientific disciplines: the physiology of work and ergonomics. In The performance of the human machine: research on work (1909)1 Amar wrote of the need for a biological analysis of social life, especially that of people at work. He analyzed human transformation of energy and developed an applied science that proportioned work to a person’s capabilities. His intent was to study human activity in order to improve social well-being.
During an official mission to North Africa (1907–1909) Amar analyzed the productive capacities of indigenous workers and prisoners at the Biskra Prison in Algeria. He collected extensive experimental data during various physical activities, including load bearing. He was interested in quantifying muscular output, which he associated with respiratory measures. Inspired by engineering approaches, he created tools to measure different types of effort, adapting the earlier studies of Paul Bert (1833–1886)2 and Étienne-Jules Marey3..
The French Ministry of Public Instruction was interested in Amar’s research and provided financial support. The reports of his studies on the optimal conditions for muscular exercise and their energetic aspects were sent to the Minister of Labour Rene Viviani (1863–1925) and President Georges Clemenceau (1841–1929) in 1909. Confronted with increasing demands by doctors, physiologists, and politicians, Clemenceau would later agree to reform health services and improve working conditions.
|Figure 2. Manner of adjusting the arthrodynamometer.
(Amar, 1915, p. 834).
Amar’s research demonstrated the need for time limits for jobs that rely on body strength. This would lead to the creation of a research laboratory on professional muscular work at the CNAM (National Conservatory of Arts and Crafts). Jules Amar became head of the laboratory in 1913 and was officially named director in 1914. His studies on mechanics applied to the human machine led him to publish The Human motor or the scientific foundations of labour and industry (1914)4. The multiple reissues and translations of this book promoted his work in other countries, explained the scientific qualities and important repercussions of the physiology of work, and helped to organize the basis of an experimental science pilot for the workforce.
Amar shared a common goal with the American engineer Frederick Winslow Taylor (1856–1915). Each wished to consider a rational use of human work (The Principles of Scientific Management5) and study human activity scientifically. Amar proposed several mechanical equations that helped quantify human work according to physiological laws of energetic systems. In this coupling of mechanical and physiological measures, he tried to objectify and predict the quantity of work an individual could provide during a given period. He studied humans at work, measured the vital energy required during physical activity, and exposed the biomechanical, energetic, nutritional, and psychological aspects of Man confronted with his environment.
The newly created laboratory was closed in October 1914 because of the war. It was transformed into a laboratory for military prostheses attached to the Health Service’s central store. Amar became the assistant director and reoriented his work toward applied research.
His starting off with a scientific analysis of motor deficits, developing an apparatus of quantification for motor rehabilitation that was used to readapt an individual to professional work. With the financial support of the Academy of Sciences, he conceived the arthrodynamometer (Figure 1), which enabled him to measure articular amplitudes and variations of strength according to their angulation, amounting to a tension-length curve of a muscle (Figure 2). He also patented several models for prostheses that could be equipped according to an individual’s needs and adapted to “universal clamp, simple or automatic” or “a ceremonial hand surmounted by a leather sheath.” He used the theoretical and technological work of his predecessors and adapted it to common postures at work, such as different locomotions, weighted steps, climbing stairs, handling wheelbarrows, etc.
Amar was an outstanding technician. He created and used modern instruments: the dynamometric bicycle and spirometer, chirograph, hand dynamometer with pear, and jointer plane (also known as the try plane or trying plane). Because he developed a mechanism to record the work carried out, he was able to invent more functional prostheses for mutilated soldiers (Figure 3 and Figure 4). He developed the foundations of modern rehabilitation methods and campaigned for the creation of a regional network center for vocational training of the disabled. The results of his experimental work, applied to many war-wounded, is recorded in The physiology of industrial organisation and the re-employment of the disabled (1918).6
All of Jules Amar’s contributions developed around three measures: the kinematic and dynamic description of the human body in movement, according to the methods of Jules Marey (1830–1904); the analysis of the energy cost of work, following the protocols of Auguste Chauveau (1827–1917); and the quantitative study of fatigue, focusing on the experiments and assessments of Angelo Mosso (1846–1910). He studied the orderly principles and methodical observation of the great organizers of industrial work, while also criticizing the neglect of psychological and physiological data by these precursors. When he gave his lecture entitled The prosthesis and the work of the mutilated7 in January 1916, he demonstrated the importance of his subject and proposed methods to assist the many who had been mutilated in the war. Indeed, while France suffered important human losses in the beginning of the 1914-1918 war, the number of wounded rescued from death, some of whom were very young, increased because of better medical care. Their survival, however, was accompanied by definitive after-effects. Records show that there were 100 000 permanent invalids, 56 000 amputees, and 65 000 mutilated among 4 266 000 wounded soldiers during this period.
Amar built on the research work of Dr. Borne, who sorted the wounded person into three classes: treatable injuries; permanently disabled with possible rehabilitation; and disabled without recourse. Amar believed that 80% of wounded soldiers could be rehabilitated. He expressed his determination to help the disabled break from simple assistance through work: “But the time has come, I believe, to organize the work of the wounded so that everyone can find his true place in the social machine.” He presented this new scientific organization in these terms: “The organization of the work of the wounded must, in my opinion, comprise three periods. In a first period, called functional rehabilitation, it’s a question of analyzing movements. (…) In a second period, efforts will be made to minimise the deficit due to impotence by an orthopedic system (…); then would begin the itself, third and last period: professional re-education.”
This method was based firstly on finding the exact measure of the deficiency, and secondly on physical strength and fatigue. In this way Amar presented professional re-education as “decisive in the analysis of all the physiological and mechanical factors of work.” The data then was collected in an aptitude sheet, a record of the physiological tests that the injured person undertook during professional reeducation. The ambition was two-fold: to adapt the diminished body to work, and to accommodate the work to the physical deficiency (Figure 5). To achieve this, Amar recommended the creation of schools for reeducation. This approach testifies to a convergence between the science of humans at work and political reformism. This convergence would crystallize during the Great War and confirm the transition from simple assistance to professional reeducation.
Amar’s legacy has unfortunately been forgotten. His works deserve epistemological interest for the initial physiological consideration of manual work. He considered manual work to be a fundamental problem of bio-mechanics to be solved and optimized. He opened new perspectives on the approach and principles of the physiology of work and ergonomics. It may be necessary to imagine oneself in the context of the time, just before the First World War, when scientists used new disciplines such as thermodynamics, biomechanics, and ergonomics to reinvent a more rational and mechanistic world with the aim of improving living conditions and life expectancy. The research, publications, and communications of Jules Amar have contributed greatly to scientific and medical fields concerning work and disability.
- Amar, Jules. Le rendement de la machine humaine : recherches sur le travail. [The performance of the human machine: research on work]. Paris: G. Baillière, 1909.
- Bert, Paul. La machine humaine. [The human machine]. Paris: Hachette, 1867-1886.
- Marey, Etienne-Jules. Animal Mechanism: a treatise on terrestrial and aerial locomotion. New York: D. Appleton & Co., 1879.
- Amar, Jules. Le Moteur humain et les bases scientifiques du travail professionnel. [The Human motor or the scientific foundations of labour and industry]. Paris: H. Dunod et E. Pinat, 1914.
- Taylor, Frederick Winslow. The Principles of Scientific Management. New York: Harper & Brothers, 1911.
- Amar, Jules. The physiology of industrial organisation and the Re-employment of the disabled. London: The Library press limited, 1918.
- Amar, Jules. La prothèse et le travail des mutilés. [The prosthesis and the work of the mutilated]. Paris: H. Dunod et E. Pinat, Editeurs, 1916.
Figure 1. Public Domain, via “Source gallica.bnf.fr/ Bibliothèque nationale de France”. http://gallica.bnf.fr/ark:/12148/bpt6k6410527t/f45.image
Figure 2. Public Domain, via “Source gallica.bnf.fr/Bibliothèque nationale de France”. http://gallica.bnf.fr/ark:/12148/bpt6k6410527t/f46.image
PHILIPPE CAMPILLO received a PhD at Montpellier University in STAPS (Science and Technology of Physical and Sports Activities), completing a thesis on the biomechanical analysis of specific sport movements. He completed a second doctoral graduate level at Lille University in the discipline “Epistemology, history of science and technology” studying the history of the theories of locomotion. His perspectives and research interests include the analysis and optimization of motor performance and the history and epistemology of science and biomechanics of locomotion.
ZIAD JOSEPH RAHAL holds a bachelor’s degree in business computing from the University of Quebec in Montreal (UQAM), a master’s degree in international management from Holy Spirit University in Lebanon, and a PhD in Science and Technology of Physical and Sports Activities (STAPS) at the University of Lille in France. He is currently working on the glocalization of sports and the biomechanical analysis of specific sport movements.