Ergograph

ergograph [′ər·gə‚graf]

(engineering)

An instrument with a recording device used to measure work capacity of muscles.

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Ergograph 

an instrument for recording the work performed by muscles during studies of the dynamics of their work capacity. Ergographs vary according to the muscles to be studied and may be classified as finger (Figure 1), hand, leg, trunk, or eye ergographs.

Figure 1. Mosso’s finger ergograph: (1) movement sensor, (2) recording unit, (3) carriage, (4) components that move the strip chart, (5) weight, (6) strip chart for recording an ergogram

The ergograph was invented in 1890 by the Italian physiologist A. Mosso. It uses special mechanical or electric sensors to record the amplitude and time of the contraction and relaxation of muscles functioning at a given rate while doing certain types of work, such as raising and lowering a weight, compressing a spring, or shifting an object of fixation between a near point and the closest point of clear vision. The subject usually operates the ergograph to the point of exhaustion, which is manifested by a decrease in the amplitude of the subject’s movements (Figure 2).

Figure 2. Ergogram of muscle fatigue: (A) optimum work capacity, (B) development of fatigue

The ergograph may be used to evaluate a person’s work capacity in different kinds of physical and mental labor or during exposure to various environmental factors. (See alsoERGOMETER.)