Evaluation of a buckle force transducer for measuring tissue tension

A buckle force transducer, suitable for measuring forces in biological materials in situ, was investigated in order to establish its reliability as a force measuring instrument. Eleven separate materials varying in shape, size and mechanical properties, were tested. Each material was repeatedly loaded and unloaded. Calibration lines, relating the applied force and the output voltage, were calculated for each loading-unloading trial. For each material, deviations between trials were calculated as a percentage of the range of voltages recorded in the first trial of that material. These data were analysed to evaluate four parameters: test-retest reliability, the effect of skewed alignment, linearity of the instrument, and amount of hysteresis present. Results indicate that the buckle force transducer used is a highly reliable and consistent measuring instrument, which behaves in a linear manner and demonstrates acceptably small hysteresis. The implications for measuring forces in biological materials are discussed.