Simple equipment to measure biomechanical quantities of muscles and organs which includes a polarity-programmable peak detector

  • D. Möller


Biomechanical measurements of muscles and organs require appropriate measuring equipment. As far as the static properties are concerned, the excursion of the bender bar of stress should be without force. The bender bar of force, however, ideally should not elongate under load. Because natural frequency is the most important boundary condition, the bender bar should be developed with this in mind. The developed bars imposed an insignificant preload to the muscle or to the organ. The small changes in resistance occurring in the resistance strain gauges affixed to the bars require the use of a highly stable amplifier. A new amplifier was accordingly developed based on the principle of an instrumentation amplifier with an integrated bridge supply and an automatic zerobalancing facility. The measured input voltage drift of the whole amplifier is less than 5nV. The maximum muscle contraction, for instance under chemical or electrical stimulation, is an important physiological quantity. Therefore, a polarity-programmable peak detector was also implemented into the equipment. The developed test set is suitable for measuring the lengths or force effects by chemical or electrical stimulation of muscles or organs. With a special bar, it is also possible to measure the degree of Parkinson tremor.


Automatic zero balance Isotonic and isometric bender bar Polarity-programmable peak detector Strain-gauge d.c. amplifier Strain-gauge half bridge 


  1. Möller, D. andBarnikol, W. (1980) Dehnungsmeßstreifen-Meßtechnik im biomechanischen Experiment.Biomed. Techn.,25, 157–162.CrossRefGoogle Scholar
  2. Véró, M. andMiller, T. (1979) Sensitive tension and force transducer.Med. & Biol. Eng. & Comput.,17, 662–666.Google Scholar

Copyright information

© IFMBE 1982

Authors and Affiliations

  • D. Möller
    • 1
  1. 1.Physiological Institute of the Johannes Gutenberg UniversityMainzWest Germany

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