Electromechanical film sensor device for dynamic force recordings from canine limbs

Abstract

An equipment based on the electromechanical film (EMF) sensors was designed for the measurementof forces acting upon canine limbs. EMF forms an elastic electret, which generates on its surface an electric charge proportional to the the force applied on it. The EMF sensors were calibrated using a conventional material testing device with cyclic loads. The beagles were trained on a treadmill working at horizontal position or with either 15° uphill or downhill inclination. The treadmill belt speed varied from 2.5 km/h to 7.5 km/h. The force under the canine paws varied depending on the inclination of the treadmill. When the dogs ran uphill, weight-bearing on hind1imbs increased 11% but the weight-bearing 0n forelimbs did not change. Downhill running increased weight-bearing on forelimbs by 8% and decreased weight-bcaring of the hindlimbs by 5%. Immobilization of the right hind] imb increased weightbearing on both forelimbs by 7-25% and on the left hindlimb by 56%. One month after a 30° valgus osteotomy operation at the right tibia, the dynamic force recorded From the operated hindlimb was 69% of the control value. Three months after osteotomy, the weight-bearing of the operated limb approached
normal situation. Our results suggest that the EMF sensor is a reliable method for the measurement of dynamic forces acting on the weight-bearing limbs of the dogs.