The aim of this final paper is to emphasize the importance of the application of kinesiological activity from the earliest age. Such activity improves the child's development with an emphasis on his functional and motor abilities. The proper development is very important at that age. The paper describes the periods of preschool and younger school children, which are divided into the phase of initiation (6-10 years), the phase of shaping (11-14 years) and the phase of specialization (15-18 years). Each age has its own developmental characteristics, and it is important that when forming an activity or training, each of these phases is respected and that we act in accordance with it. From the very beginning, play, through which chilren develop their abilities, is extremely important. The older the child, the more agile and strong he is, and thus he can withstand a greater load. It is important not to skip children's developmental stages and not to give them more than they can handle. The performance abilities of children are affected by the rate of growth of their bones, muscles, organs, and nervous system varies in certain developmental stages. Assessment of motor skills is of particular importance during the preschool and school years, as it is used as a monitor of developmental changes and identifier of developmental abnormalities. Exercise in children can be focused on the general development of the locomotor system and on exercises to strengthen weaker muscles. It is important to engage the whole body and pay a little more attention to the muscles of the torso and back and, if necessary, the feet. Strength and flexibility exercises should be added to such exercises. The facilitator or trainer should choose a balanced program of exercise that will not be monotonous, that provides children with benefit, pleasure, and fun.