Mosso Ergograph

From Dead Media Archive

Jump to: navigation, search
The Mosso Ergograph (1890) was invented by Angelo Mosso to measure the optimum stage of muscular performance in human beings. Mossos's main interest in the instrument was because of its potential to measure fatigue. However, it also enabled the testing of many complex variables and their effects on muscular strength, such as a lack of food, sleep, forced marches, mental fatigue, and the effect of substances such as coffee, sugar, and even emotional affect. The Mosso Ergograph was, however, deemed too problematic and was phased out of physiological research early in the 20th century. The word ergograph is derived from the Greek erg meaning a unit of work, and graphe (writing) from graphein which is to write.
Early photograph of the ergograph


Contents

Precursors to the Ergograph: The Dynanometer and the Myrograph

  • The dynanometer stands as the motor-sensory predecessor to the ergograph in that it was often used to determine the maximum force of a muscle or to compare movements of the same estimated force. James Baldwin describes it in his Dictionary of Philosophy and Psychology as a device that can be compressed or pulled apart in the sides and the amount of force exerted in either case is indicated on scales by a pointer to measure the highest point reached. (Baldwin 607)
  • Mosso criticizes the use of dynanometers for measuring muscular force by saying they did not produce constant indications, a criticism that also applies to his own research on the subject. The issue Mosso found with the dynanometer was that fatigue could not be isolated in one muscle alone, once one muscle is fatigued other muscles take on a greater role in the movement (Mosso, 83).

The myrograph designed by Hermann von Helmholtz is the direct, mediatic predecessor as it included the graphing of sensory input. The device, created in 1872, addressed the nature of the nervous current by recording the contraction of the muscles extracted from frog's legs (Mosso, 76). This was a device that allowed for the measured recording of muscular work that our senses would be too slow to grasp. The Mosso Ergograph is remediation of both of these instruments.

Picture and Description of the Machine

Parts – Mosso’s Ergograph – Description

The introduction of this instrument to study muscular strength attempts to conform to the paradigm modern scientific method and attempted to assimilate many of its aspects , including the laboratory space, an emphasis on applicability, and the standardization of procedure. The parts of the machine are clearly visible to the human eye with a few exceptions. The pictures seen here are included within Angelo Mosso's book Fatigue (1904) along with his description of the parts of the machine (Mosso, 86). The machine is composed of two parts: the supporting and registering platforms. These two parts are fixed atop a large table upon which the subject lies supine, with their arm attached to the machine.

The Supporting Platform of the Ergograph (Fig. 1) consists of a plate, upon which are two fixtures that conform to the shape of the dorsal aspect of the hand and the forearm (A and B in the diagram respectively). The forearm and the hand face up when placed within the machine, and hold place at the wrist by two metal clamps (C and D) which are then secured tightly to the wrist by turning the screws at the top of each mechanism. When using the right hand, the index finger is placed into tube E, and the ring finger into tube F, while the middle finger is attached to a string by use of a leather strap connected to the registering apparatus. To ensure a comfortable position of the arm, the supporting platform is placed on an 30 degree incline so that the arm is not in full supination. When the left arm is being tested, the supporting base can be adjusted by the triangular support (G) at the base of the platform.

Figure B from Mosso's Fatigue

The Registering Runner of the Ergograph (Fig. 2) connects to the supporting platform by a piece of iron which is connected at positions I and H. It runs underneath the table and cannot be seen when examining the artifact from above. The string attached to the middle finger contained within the supporting platform is connected to the end of the registering runner, and runs along the structure by the use of hooks. The register consists of an iron platform, with a brass fork column (M) upon which connects two steel rods guided into a metal runner (A,B). The metal runner holds a pencil which marks the amount of contractions in the middle finger, by registering them upon a piece of paper (D). The string also runs through this section of the machine, threaded through the metal runner, connecting to another cord that passes over a pully and is attached to a weight of three or more kilogrammes. Between two intervals of contractions, a button is pressed (C) which moves the paper one milimetre to the right in the transversal platform (F). This way contractions can be measured in succession to respond to the raising of the of the weight by the middle finger.

Figure A from Fatigue

When a hand and arm are placed within the machine, the subject is instructed to contract and flex the middle finger. The height of the contractions, or rather the height of the weight when raised by the contraction, is then represented graphically on the piece of paper placed in the transversal platform. The contractions are done in regularity, through the use of a metronome which strikes every two seconds. The input of the machine is thus literally digitized, the fingers through discrete movements of contraction and release provide the information for the graph. The graph itself however is continuous, an analogue function. The graph resembles a wave, and demonstrates the total amount of finger contraction when pulling the weight (represented by the height of the line) which is then followed by a curvature of the line downward when the finger is relaxed. The curve normally decreases in a relation to the number of contractions made - each length gradually decreasing as the work continues. As the person becomes more fatigued, the movement ceases.

Image of hand strapped to apparatus

The apparatus, with its form so specific to the human arm, requires the presence of a human being for the functioning of the machine and the experimental process. The machine, controlled by levers and weights, has no movement aside from the contractions being made by the middle finger of the subject. The subject therefore becomes a variable of the machine, and precautions are taken in ergographic experiments to attempt to ensure replicability in later studies. The human subject is complex, individual differences are apparent in the study of fatigue, and differences are seen in how energy is consumed in producing muscular energy from subject to subject (Mosso 244). The time and amount of food, as well as sleep, physical activity mental activity and the introduction of other substances such as caffeine or alcohol can have profound effects on the experimental process in ergographic research (Rivers and Webber 34).

Efforts must be made to keep the conditions of these activities as constant and uniform as possible, so as to not compromise the experiment. As well, the condition of training of the muscles must also be taken into account in ergographic research, and some scientists would refuse to test the influence of a drug or other condition on fatigue until the signs of imperfect muscular training (seen through muscular pain and an irregular ergogram) had disappeared. According to Vilém Flusser, the second Industrial Revolution brought on a reversed relationship between human being and tool (Flusser 45). With the change from tool to machine, human beings switch from being the constant to the variable. With the second Industrial Revolution, the human being is the variable and the machine is the constant; a relationship which can be seen very clearly in the case of the ergograph. To conform to the machine and the experimental process, precautions are taken to standardize human activity. Mosso observed that it in order to obtain the same curve of fatigue every day in a succession of trials, it was necessary to maintain the body under identical conditions, "let one digest or sleep badly or indulge in any excess whatever, and immediately the curve changes." (Mosso 1904: 94)

Graph: Assessment

The curve of fatigue represented by the graph is relatively easy to understand, the longer the line, the greater the contraction of the finger attached to the weight. Shorter lines therefore represent that the subject was unable to bend the finger to full contraction. For the average individual not acquainted with the reading of graphs, a scientist would be needed to interpret the graphic representation as information. The interpretation of the data in relation to successive experimental trials would necessitate knowledge only available to the researcher.

Analysis of the Materials Used by Mosso

Perhaps because of its high malleability and affordability, brass was used commonly in making laboratory equipment, and became the standard for weights and measures in England and other European countries. (McCulloch, JR, & Vethake, H, 1852: 161).The four cushions, A, B, C and D are made out of hollowed-out brass. The tubes E and F are also made of brass.

The register platform is made from iron - also commonly used in laboratory equipment because of its low cost and high strength. The platform holds two little brass columns forked to support cylindrical steel rods. Steel replaces iron, which is considered too soft for some equipment. The other materials needed in order to construct an ergograph would include the leather binding used to tie the finger down to the apparatus, and the string to tie the weight to the apparatus was composed of cat-gut, suggested by Mosso because it was used in violins and cellos for its was durability (Mosso, 88). The graph is inscribed paper (some models use a kymograph) upon which a stylus moves back up and down to represent and inscribe the changes that gives a graphical representation of spatial position over time.

The time-frame in which the ergograph was created and active was the ‘brass age’ of psychology, approximately between 1880-1910 (Coons 767), and as one of such numerous psychological ‘laboratory’ media, it embodied the technoscientific ideal because only in the 19th century had the standardization of weights and measures, together with new methods of precision machining, made possible the quantity production of standardized laboratory instruments.

Standardization itself lends legitimacy to the ‘hardware’ as the launching point for psychological practices, because "it itself was standardized and regulated the production of physical stimuli to which the observer would respond, and it also gave quantified, standardized output to the introspective method. In the manufacture of psychological knowledge, standardization of both process and product now seemed possible” (Coons 770).

The Ergograph as an Extension of the Body: Analysis and Implications

Mosso designed the apparatus ergonomically, tilting the machine to make it more comfortable for arm placement. Clamps are put in to constrain the ways in which the muscles and body can move during testing. The objective was to isolate the finger, iin order to create a direct relationship between work performed and an increase in fatigue. The clamps were placed to isolate the muscles as much as possible, as researchers of the time such as Bergstrom and Binet were concerned, and allow for the arm to be as much of an isolated environment as possible, to act and be acted upon in a laboratory setting (Bergstrom, 86-87). The intention behind it, as John Bergstrom claims, is to study the action of isolated muscles or single muscle groups and ending with that which brings into play many, or nearly as may be, all the muscles of the body” (246). This is a determined, systematic spreading from muscle sites to an entire mapping of the body (Foucault). The individual body parts became, as the core object of study in physiology of the 19th century, what Jonathan Crary would call the 'bio-power' or 'bio-politics' of populations and control over individuals. In his seminal text Techniques of the Observer, he notes that "it is indeed life that emerges as the new object of power", and the "knowledge [conditioned] by the physical and anatomical functioning of the body, and perhaps most importantly, of the eyes" ushers in the appearance of new methods of power" (Crary, 79-80). New optical apparatuses such as the stereoscope operated as mechanical prostheses that began to define the body by its discrete parts. This concept, also known as metonymy, would highlight an individual sense to speak for the body as a whole, where the sensory faculty such as the motor-sensory reflexes for the ergograph, would be considered contiguous with the instrument itself. Equal within a shared plane of operation, and differing only in the extent of their respective capabilities, the machinery long surpasses the human sense faculty and accentuates our capacity to observe changes in motor-sensory experience (Crary,129)

Criticisms of the Ergograph: Late 19th and Early 20th Century

  • John A. Bergstrom as well as Binet and Vaschide (1897) argue that Mosso does not fulfill the ideal that he himself calls for, which is the complete isolation of an individual muscle in order to measure fatigue in a pure relationship, “as nearly as possible like those in experiments with excised muscles (Bergstrom 1903:247 )

Mosso was incorrect about which muscles were the ones needed for the ergograph: the lumbrical and palmar muscles are involved along with the muscles he had isolated before, the flexor sublimis and flexor profundus (Bergstrom 1903:247)

  • The binding of the apparatus itself is a potential source of error. There are accounts of difficulties in securing the desired isolation and in maintaining the same position because of the rigid supports used to clamp the arm and hand down. Bergstrom notes that when the body is taxed with effort, movements of the entire arm and even the rest of the body will aid in the effort to displace the hand or help in raising the weight, which would affect and throw off the results taken by the ergograph. The sheer materiality of the machinery itself obstructs pure results.

Binet and Vaschide in Examen Critique de L'Ergographie de Mosso (1897) mention the large and awkward nature of the instrument itself and that it requires constant maintenance.

  • Limitations: The ergographic record is “a test of some general physiological condition” (273), as already mentioned because of the variation of human experience can affect the results. There is also the problem of whether the character of fatigue can be attributed solely to the isolated muscle or to a general state of fatigue (274).Bergstrom concludes by saying that, “With these many factors to obscure the result and with fatigue partly a local phenomenon, we cannot expect to use the ergograph as a measure of exhaustion in the same way as we use a thermometer to measure temperature, but it may do a very important service in aiding us in its field of application to analyze the conditions and effects of work and fatigue” (275).

This does not mean; however, that Mosso, Bergstrom and other physiologists and psychologists experimenting with the ergograph in this time period assumed that the results would lead to a direct and simple correlation between work and fatigue. Bergstrom cautions that one is not to discount the properties of the central nervous system in affecting and stimulating the muscular forces, because the fatigue experienced can certainly be affected by psychic factors (Bergstrom 273).

  • Problems with design and possible improvements: spring vs. weight Mosso assumes that the total work which a muscle can do before it is fatigued is equivalent to the sum total of the height of the separate contractions represented on the graph (Franz, 351). Binet challenges such an assumption by saying when a muscle can no longer lift the weight specified by the ergograph, it can perform once more at a smaller weight. Also, when a muscle strains against a weight it cannot lift, the physiological work done in the attempt to complete the task is considerable, although the muscle cannot accomplish the mechanical work. This is the main objective that led Binet and others to devise spring ergographs to counteract the perceived weaknesses of the Mosso ergograph. With the spring the subject does not have to work until the subject is completely fatigued, and can continue to work at lower resistances for longer periods of time.(Franz, 351) The spring ergograph supported by Binet and others were devised because they maintained that under 'normal conditions', the muscle never comes to a state which is incapable of work, and a spring ergograph is more representative of this phenomenon. This would increase the generalization of the ergograph to normal working conditions.

Socio-Historical Backdrop

Angelo Mosso

Angelo Mosso with one of his many physiological apparatuses
  • The Mosso Ergograph (1890) is named after its founder Angelo Mosso (1846-1910), an experimental physiologist from Turin, Italy.(1946: 880) His experimental interests were were focused in the areas of fatigue, sleep, movements of the intestine, animal behaviour, the brain, fear and education. He died of diabetes on Nov. 24, 1910.
  • Angelo Mosso's interest in research on fatigue began when he arrived at the Leipzig laboratory in 1873, an area known for producing psychologists and physiologists who were interested in the use of instruments to record and measure vital and mental processes. (Drummon vi; Mosso 81)Notable theorists who came out of the University of Leipzig and contributed to this research include Willhelm Wundt, Ernst Weber and Gustav Fechner, all known for their early contributions in the field of experimental psychology. Mosso's own work was within the field of physiology, a field which contributed to the development of experimental psychology and later Behaviorism.

History of the Ergograph and Physiological Research

  • The study of the nervous system in the discipline of physiology began with Johannes Muller and his work on sensory experience. (Mosso 74) In 1850, Hermann von Helmoltz continued research on the sensory stimuli and the nervous system, and is accredited with being the first to shed light on the nature of the nervous current. Helmholtz constructed a machine to record the contractions of the muscles, the myrograph, which was the first graphic method to measure the length of time of the nervous current along the nerves. Mosso argues that the human eye itself is not sufficient to comprehend the speed by which a phenomenon like muscular shock takes place. (Mosso 77) The graphic methods supplied by both he and Helmholtz produce a record which is representative of the "minutist particulars of movement," unveiling an entirety of phenomena that would have remained obscure if left to human observation alone. Jonathan Crary argues the nineteenth century marked the beginning of the creation of a new "objectivity" accorded to subjective phenomena and was indicative of larger changes occuring within modernity. (Crary 10;98) The ergograph attempted to contribute to this mapping of the human sensorium, in an effort to determine a continuum of productivity, specifically for educational practices.
  • Mosso's interest in the complicated process of fatigue was intertwined with his research in education. By using the ergograph, Mosso thought he could find a relation between muscular strength and intellectual work; and it becomes clear that what Mosso was attempting to study was not fatigue, but attention (See section on Attention). Mosso attempts to speak of muscular fatigue and changes which take place in the muscles, only for a better understanding of fatigue in the brain. (Mosso 129)It appears that Mosso attempts to study two types of fatigue by use of ergographic research. In a material sense, he is studying the fatigue in the isolated muscle itself, shown as a function of when it stops responding on the graph, but he is also trying to determine the "feeling of fatigue," the internal sensation of the individual when muscles are strained. In isolating the muscle of the hand, Mosso is attempting to test an economy of attention. In his view attention is the inhibition of other activities, in favor of a single, focused activity.

Philosophical Background

  • The ergograph follows an empirical framework, and is an attempt to use modern scientific methods for a study of muscular strength and fatigue. Like most physiologists, he is grounded in the philosophy of materialism, holding that mental phenomena are a function of the brain. Materialism, the argument that everything is materially constituted including human beings, is in opposition to dualist theories that posit a fundamental difference between the physical realm of the external world and the non-physical realm of the mind. Closely linked with materialism is the concept of mechanism, to which Mosso also ascribes, arguing that all of the phenomena in nature must have a cause. While Mosso does not claim that physiology could comprehend the mysteries pertaining to the nature of the mind and thought; he claimed that physiology did not renounce hope of doing so in the future.

Mosso Ergograph and Research into Education

  • Angelo Mosso states in his chapter "Exhaustion," a machine recognizes no limit to its speed save the weakness of man in performing his part as assistance” (Mosso 172). The sociocultural and historical backdrop of industrialism provides a basis to understand Mosso's development of the ergograph in physiological research. The introduction of the study of psychology in experimental psychology by Wundt, Weber and Fechner introduced many instruments invented to record mental processes. Mosso's ergograph, although within the discipline of physiology, is very similar in nature. His interest in studying muscular strength and its relation to mental fatigue, were used in educational practices during this period. (Drummond vi) For instance, in measuring times of the that schoolchildren were more or less receptive to incoming information, as well as the best divisions of the school day in relation to play and work.
  • In Karin Johannison’s “Modern Fatigue: A Historical Perspective” (2006), fatigue was commonly associated with two factors: industrial work, and intellectual work. With industrial work, the human being was seen as a machine, a metaphor for the body which had arisen from a century prior to the introduction of the ergograph. This logic enabled the rise of physiological and early psychological instruments measured the performance of the body and likened it to the factory machine, where “both represented motors that changed energy into mechanical work; in conditions of imbalance, exhaustion, or overheating their efficiency would be dramatically reduced” (7).
  • The ergograph is one of many of such laboratory devices used on the industrial body, isolated individual parts of the human body in order to determine the productive capabilities of the body as a whole.
  • Johannisson argues that scientists were investigating all manners of work and exhaustion, because they wished to map out the body’s energy system, economy of muscle energy and pinpoint the difference between exhaustion and overstrain (Johannisson 7) . The underlying motivation of this enterprise was the desire to define “the borderline between the normal and the pathological, or between capacity and incapacity, respectively, after recuperation through rest” (Johannison 7-8).
  • Fatigue in intellectual work was not to be discounted. The ergograph was used to research fatigue in connection with groups that had a high consumption of mental activity, such as students, scientists, and intellectuals, (i.e., ‘‘brain-workers”) (Johannisson 8) . According to Johannisson, apparatuses such as the ergograph were measuring exhaustion with the need to find the “strategic threshold value for the individual’s adaptive capacity to modern society” (8). She adds, “The fatigue problem was a social problem, the responsibility of which therefore had to be shared by the areas of medicine, technology, education, and politics” (8).
Subject Connected to Ergograph.

Examples of Experimental Research

  • In Fatigue, Mosso mentions his brother investigating the influence of cocaine on the phenomena of attention. It was already known that certain stimulants, such as alcohol and coffee shorten reaction time. About half an hour after taking from five to ten centigrammes of cocaine, one experiences a sensation of excitement and well-being which lasts about an hour (Mosso 205).
  • Rivers and Webber used a “greatly improved form of Mosso’s ergograph devised by Kraepelin and made by Runne” in a 1907 experiment to study the effect of caffeine on the capacity for muscular work (Rivers and Webber 34). They found the increase is temporary, in the beginning of the set, and falls below normal towards the end. They could thus see the withdrawal effects of caffeine.
  • A report by a Great Britain Liqour Traffic Central Control Board advisory committee (1918: 48) cites a 1904 study by Hellsten using an ergograph that measured movement being executed by both arms to measure the influence of alcohol on an athlete By Great Britain.

Controversial Usage of the Ergograph in Research

  • In 1898, G.C. Ferrari deviated in the use of the ergograph to study gender differences in intelligence as a function of handedness. His study attempted to find differences in fundamental character between women and men that were being reflected by the ergographic tests. The test strives to show that women in the left hemispheres are less coordinated than men. H.C. Warren commented upon seeing this study was flawed from its conception, expressing to see more results done on this study because its claims were too radical in nature.
  • In 1898, 1,400 school children from Chicago were “examined” for three months using a Mosso ergograph referred to as the "child fatigue testing machine", to determine whether “after a certain age is reached should the girls and boys of the public schools be separated in their school work and different tasks be assigned to each ("Medical Matters...", 1899).

The Valuation of Types of Labor

Johannisson states a marked hierarchy between the fatigue levels obtained by manual labor versus intellectual labor, where the ergograph would supposedly be able to distinguish differences between the two, where researchers tried using the medium to demonstrate that “intense mental strain caused by tasks such as solving a mathematical problem or memorizing Latin or poetry also caused muscle fatigue” (8). Underneath this expectation of distinguished results between different levels of fatigue comes a hierarchical distinction made between the fatigue that the manual worker and the intellectual worker experience, where mental work is thought to be more energy-consuming than heavy industrial work or mechanical office work. The effect of brain stress on the body seems to hold the assumption of seeming greater than direct stress on the body, where the ancient dichotomies of order between soul and body and the work of the elite and the masses come into play.

In Angelo Mosso’s Fatigue, the ergograph is already thrust into educational settings, where fatigue becomes an important factor within education. Only recently, Mosso notes, has it attained the status of a scientific concern, and “thanks mainly to the impulse given by the wonderful patience and ingenuity of the Leipzig school of psychologists” (Weber, Wundt, Fechner) (Mosso 29) scores of instruments have been invented to record and measure the vital and mental processes. This allows the Mosso ergograph to make observations on school children with the intention of determining the degree of fatigue, the peak periods of educational productivity, and the best division and organization of the school day in regards to play and work. All of this points to the Foucault notion of docile bodies within institutions that strive to obtain an optimal peak of efficiency in order to standardize their subjects into a pool of profitable personnel.

The Mosso Ergograph and an Economy of Attention

The human faculty of attention became a serious site of exploration around the time the ergograph made an appearance as well. The underlying historical platform houses the division of holistic completeness of the classical body in contrast with the fracturing of the modern body in the 19th century. The modern body is fractured into its discrete parts, accentuated and aggravated to go beyond what it is normally capable of enduring, much in the way the visual faculty of image-retention and after-images is explored by the likes of Jan Purkinje, when "the threshold between the physiological self and the mental became one of the primary objects of scientific practice" (Crary, Pg 102). Goethe before him had established the idea of subjective visual phenomena such as afterimages at the level of a new sensory 'objectivity', because whatever the healthy corporal eye could perceive was in fact optical truth (97-98). This idea of a new objectivity that could be understood and used to master the human body is one of the driving intentions behind the ergograph's built mechanisms. Arthur MacDonald makes such a connection between the visual sensory equipment such as the stereoscope, a medium that Crary notes dominates and trains the viewer to ‘see’, with the ergograph, especially noting the way the modern body reacts to fatigue. When pushed beyond the threshold, the body engages in “a number of phenomena in which fatigue causes a periodicity depending upon the central nervous system. This is probable in the ‘second wind’ of the athlete. The intensity of after-images is due to periodic variation” (Pg. 1178). The periodic variation of the ‘second wind’ with that of the afteimage, as mentioned in Crary, is a reference to the exertion of the body past its optimal performance, where the body is extended beyond the norm, finally dividing the actions of the body from that of the mind out of sheer necessity.

Successors to the Mosso Ergograph

After the faults of the ergograph was made clear, it was slowly phased out at the beginning of the 19th century, and the dynanometer was quickly reintegrated. As to a contemporary correlate of the ergograph, this can be seen in ergometers, or in other words, common-day gym equipment, such as rowing machines, stationary bikes, and treadmills. These technologies are used to measure strength and integrate modes of resistance, but do not necessarily produce a graphic record like that of the ergograph.

Ergometer test taken in Outer Space!


Terry Gilliam's creative interpretation of medical ergometers in Brazil

Citations

1946. "Angelo Mosso, 1846-1910." in The British Medical Journal1: 880.

2003. The Chambers Dictionary. Edinburgh: Chambers.

Baldwin, James Mark. The Dictionary of Philosophy and Psychology, Vol. 3, Part I. MacMillan Company, 1901.

Bergstrom, John A. "A New Type of Ergograph, with a Discussion of Ergographic Experimentation". The American Journal of Psychology, Vol. 14 No. 3/4. Jul-Oct 1903. University of Illinois Press.

Binet, A. and Vaschide, N. 1897. "Examen Critique de l'Ergographe de Mosso." in L'Année Psychologique4:253-266.

Crary, Jonathan. Techniques of the Observer: On Vision and Modernity in the Nineteenth Century. MIT Press, 1992.

Drummond, M. and Drummond,W.B. 1904. "Translator's Preface" Pp. v- viii in Fatigue. New York: G.P. Putnam's Sons.

Flusser, Vilém. The Shape of Things. Reaktion Books, 1999.

Franz, Shepherd Ivory. "On the Methods of Estimating the Force of Voluntary Muscular Contractions and Fatigue". American Journal of Physiology, Vol. 4, 1887.

Johannisson, Karin. Modern Fatigue: A Historical Perspective. A Multifaceted View of Stress. Ed. Dr. Bengt B. Arnetz, Prof. Rolf Ekman. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Lanska, D. 2000. "William Hammond, The Dynanometer, The Dynanograph" in Archives of Neurology 37: 1649-1653.

McCulloch, JR, & Vethake, H,. 1852. A dictionary, practical, theoretical, and historical, of commerce and commercial navigation. A. Hart

Mosso, A. 1904. Fatigue. "Translated by M. and W.B. Drummond." New York: G.P. Putnam's Sons.

"Medical Matters in Chicago". September 9, 1899. The Medical news. Henry C. Lea's Son & Co.

Rivers, W.H.R. and Webber, H.N. 1907. "The Action of Caffeine on the Capacity for Muscular Work." in The Journal of Physiology.XXXVI 3:33-47

UK Central Control Board (Liquor Traffic) Advisory Committee. 1918. Alcohol: Its Action on the Human Organism. Longmans, Green and Co.

Warren, H.C. 1898. "Ricerche ergografiche nella donna." in Psychological Literature:547.

Personal tools