The cerebellum affects a number of important and complex processes in the organism. It ensures coordination, motor learning and plays an important role in cognitive and affective functions. In the case of cerebellar degeneration, we find not only the movement disorders but also behavioral abnormalities, collectively referred to as cognitive-affective syndrome. The aim of this work was to investigate motor functions during ontogenesis in animal models of hereditary cerebellar degeneration - mutant mice Lurcher and Purkinje cell degeneration using the device for quantitative gait analysis and rotarod. In addition, the effect of physical activity on the extent of ataxia and manifestations in classical behavioral tests was monitored. The results confirmed significant differences in motor skills between mutant and healthy mice; differences were also observed in some gait parameters, especially in walking speed and parameters that correlate with it. The motor functions of most groups of mice did not change during ontogenesis, pcd mice deteriorated their performance on the rotarod. The effect of physical activity was not found, with the exception of Forced swimming test. Physical activity of set intensity did not have any beneficial effect on the motoric manifestations of the mice.