Inductive displacement gauge.

Strain gauges are often used for the measurement of contractile activity of muscle tissue. In these cases the strain gauge is used as a force measuring device. Because of its stiffness, the strain-gauge-type transducer resists changes in length produced by contraction, and this could cause secondary effects. This paper describes an alternative method to evaluate contractions. Displacement rather than force is measured. The device offers very little resistance to motion and thus does not constrain the tissue. The sensitivity of the transducer is very high. An additional feature is the low cost of the transducer compared to strain-gauge devices.