Motor activity is one of the essential means of shaping strong health and of a child's harmonious development in the contemporary school. This study is intended to estimate the physical development of children from Moscow primary schools who either attend or not attend sport clubs after lessons. The study findings suggested that the most advantageous sports for harmonious physical development of primary school students are different types of martial arts, sports gymnastics and acrobatics, because rather high results of physical development of static endurance of body muscles were observed. In the group of children attending athletic gymnastics and acrobatics, the high indicators were demonstrated in three of four test exercises. No significant differences were found when testing the balance and strength of finger flexors of children in comparison between groups by sports types, and the intra-group differences are observed in the group of children attending such clubs as football, swimming, karate, aikido and boxing, ballroom dancing, ballet, and cheer leading. The children who did not attend sports clubs after lessons demonstrated medium results in many test exercises. For instance, based on the results of the side plank, handgrip dynamometry and equilibrium tests, more than 40 % of children demonstrated asymmetry, which testifies to the inefficient system of the physical exercise lessons and other active forms of schooling. The study findings allow judging about the benefits and deficits of the teaching techniques and physical exercise arrangements in the studied sports clubs for the primary school students.