The aim of this study was to describe the activity pattern of the Musculus quadriceps femoris, the ground reaction forces and kinematics of the hind limb of walking dogs as well as an analysis of a possible correlation. Ten clinically sound Malinois (Belgium Shepherd Dog) provided from the Department of Defence of Slovenia were used for the measurement. Light reflective spherical markers were placed on the skin above certain touchable bone points of both hind limbs. The surface electrodes were positioned on the shaved and cleaned skin above the M.
quadriceps femoris (M. vastus lateralis) of each hind limb. The recording of the electromyogram, kinetic and kinematic were running simultaneously at a treadmill velocity of 1,22 m/s. The M. quadriceps femoris of walking dogs shows an activity pattern with two maxima. The first maximum begins just after the beginning of the stance phase and a ¿valley¿ follows in midstance. Then there is a second maximum with smaller amplitude. Before the end of the stance phase a fast reduction of the activity follows. In the swing phase the muscle shows a minimal activity (65 ¿ 85 % of motion cycle), but a little bit before the end of the swing phase the acticity grows very fast. The femorotibial joint shows at the passage of the swing to stance phase the greatest extension when the foot touches the ground. The first maximum of the electromyogram takes place earlier as the first maximum of the ground reaction forces, because the muscle has to absorb the forces acting on the stifle joint to avoid bending of the limb. Up to midstance the extension of the stifle reduces a little bit and at the second half of the stance phase it reaches approximately a zero position. This is done by the second activity maximum of the EMG and gives the required stability of the stifle joint to lift up the paw just before the end of the stance phase. That represents the second maximum of the ground reaction forces. This is granting the forces required for the forward movement of the body. A little bit before the end of the stance phase there is a short increase of the extension whereas the ground reaction forces and the muscle activity decreases. Together with a fast flexion of the femorotibial joint at the beginning of the swing phase the muscle activity decreases. Just before the end of the swing phase (85 % of motion cycle) the activity of the muscle increases very fast and the stifle joint extends.