Ergography and Ergograph

ERGOGRAPHY, ERGOGRAPH (from Greek ergon work and grapho write), an instrument and method proposed by Mosso for recording work. The ergograph consists of a stand for the forearm and a device for recording the movement of a load (Figure 1). To ensure immobility of the forearm, the stand is equipped with clamps. The fingers are placed in metal tubes, of which only one—for the middle finger—can move up and down; a thick string (from a cello) is attached to this tube, and at the other end, passed over a pulley, hangs a weight. During the contraction of the muscles of the middle finger, the string lifts the weight upward, and a pen attached to it records the elevations and lowerings of the weight (the ergogram) on a kymograph. Binet proposed making the tube for the middle finger out of two parts: stationary and movable; then the tube, representing as it were a finger joint, provides more natural conditions for its flexion. Binet also constructed an ergograph with a spring replacing the weight.

Figure 1. Mosso's ergograph.

Henry proposed a very simple and cheap mercury ergograph, consisting of a rubber bulb with a rubber and then a glass tube extending upward from it. Everything is filled with mercury, upon which a float with a horizontal pen swims in the glass tube. Upon compression and decompression of the bulb, the mercury raises and lowers the pen, which records the ergogram. The Dubois ergograph is built on the same principle (Figure 2) as Mosso's, but the recording is done with a pencil on paper placed in a carriage moving perpendicularly to the movement of the pencil. The movement of the carriage and the work are performed by the flexing index finger (via a special transmission mechanism). The four non-working fingers grasp a vertical wooden post. A disadvantage of the ergographs of Mosso and Dubois

Figure 2. Dubois's ergograph.

is that, despite their fixtures, they cannot completely isolate the working muscle from the non-working ones. With strong fatigue of the working muscle, the non-working ones begin to assist it. Ergographs exist for the biceps, neck muscles, and legs. Sechenov constructed an ergograph for recording the sawing movements of the arms. Mosso and Dubois ergographs are commercially available in the USSR. The Dubois ergograph is significantly cheaper than the Mosso ergograph because it does not require a kymograph. A tremendous number of experimental works have been performed with ergographs to study fatigue in adults and children, in factories, schools, and laboratories. The study of the obtained ergograms from a mathematical point of view made it possible for Joteyko to express the work (at a pace of 30 times per minute) produced on the ergograph by a third-order parabola formula: n = H - aP + bt² - ct³, where H is the maximum effort (in mm), n is the desired effort, and a, b, and c are constants. Early experiments by Mosso showed that mental fatigue reduces work on the ergograph. Further research in ergography has shown that four types of ergograms are obtained, having: 1) a convex shape at the beginning, 2) a steady gradual decrease in elevations, 3) after initial large elevations, a rapid drop in their height, 4) a convex shape in the middle. Based on the study of ergograms, attempts were made to rationalize the work of schoolchildren. By examining ergograms before and after industrial work, the fatigue of workers in factories, in garment, porcelain, and other industries was also judged. During repeated work on the ergograph, strong trainability is observed, expressed especially in the prolongation of the onset of the moment of refusal of the muscle to lift a given weight. Treves showed that a muscle that has refused to lift a given weight can lift a smaller weight without rest; the same rule exists for pace. Yefimov found that when lifting a medium weight to the same height at the maximum possible frequency, the obtained "maximum frequency" ergograms show not a gradual, but a stepwise drop in performance; about 5 steps are formed. Ergography serves to detect diseases of the muscles and nervous system. Neuropsychiatric patients, e.g., hysterics, show characteristic deviations from the ergograms of healthy subjects. Schultze and Chuchmarev studied the emotional state of the subject through work on the ergograph. The ergograph is also used to study the effect of alcohol, tobacco, caffeine, etc., on the human body. Lit.: Binet A. and Henry V., Mental Fatigue, Moscow, 1899; Yefimov V., Studies of Worker Fatigue as a Method for the Scientific Determination of Production Norms, Gigiena truda, 1923, no. 8-9; Mosso A., Fatigue, St. Petersburg, 1899; Whipple G., Manual for the Study of Physical and Mental Activity of School-Age Children, Moscow, 1893; Schultze R., Practice of Experimental Psychology, Pedology, and Psychotechnics, Moscow, 1926; Joteyko J., Lois de l'ergographie, Inst. Solvay, trav. du lab. de physiol., vol. VI, 1904; Efimoff W., Versuch die nerven-geistige Tätigkeit und Ermüdung vom Standpunkte einiger Gesetze d. physikalischen Quantentheorie zu untersuchen, Scientia, vol. LIV, 1933.