Mosso Ergograph

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The Mosso Ergograph is a machine designed to find a body’s individual optimum stage of muscular performance (Bergstrom, 271-271). It is a machine that allowed for 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 (Bergstrom, 273-274).


Precursors – dynamometer, myrograph

The dynanometer stands as the motor-sensory predecessor to the ergograph in that it was 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, 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.


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.

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.

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.

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 – how it was measured, how to read it

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.