DYNAMOMETER FOR RAT PLANTAR FLEXOR MUSCLES IN-VIVO

A dynamometer is designed and fabricated to measure the force output d uring static and dynamic muscle actions of the plantar flexor muscles of anaesthetised rats in vivo. The design is based on a computer-contr olled DC servomotor capable of angular velocities in excess of 17.5 ra d s(-1). The system controls the range of motion, angular velocity and electrical stimulation of the muscles, while monitoring the force out put at the plantar surface of the foot. The force output is measured b y a piezo-electric load cell that is rated at 5 kg capacity. Angular v elocity and position are measured by a DC tachometer and potentiometer , respectively. All measurement devices are linear (r(2)=0.9998). The design minimises inertial loading during high-speed angular motions, w ith a variation in force output of less than 0.2%. The dynamometer pro ves to be an accurate and reliable system for quantifying static and d ynamic forces of rat plantar flexor muscles in vivo.