Abstract
Introduction. Periodically, at the turn of August and September the problem of overloading children with too heavy schoolbags rises and it may initiate various disorders not only around the spine area. Material, method. The research on body posture was carried out in a group of 65 7-year-old students by Projection Moiré in 8 positions. First position – habitual position, second – after 10 min. of asymmetric loading on the left or right shoulder, third – after 1 min. of the load removal, and fourth – after 2 min. of the load removal. Results. There were analyses of significance of the differences between 1st and 2nd, 1st and 3rd, 1st and 4th, 2nd and 3rd, and 3rd and 4th measurement to determine the influence of loading and correlation of the differences with physical activity. It was also measured, which way of carrying disturbs the body posture less.
Conclusions.
1. A four-kilograms load of school supplies carried on the left or right shoulder disturbs significantly and negatively biomechanical body statics of a 7-year-old child, which may cause errors in long term perspective and consequently body posture disorders. Relatedly, this way of carrying school supplies is not recommended to first graders.
2. Physical fitness has more significant meaning in biomechanical body statics disorders in frontal plane than in sagittal and transversal plane, relatedly among boys than girls. Endurance and strength show the most common correlations with changes of values of body posture features. In sagittal and transversal plane speed and strength have the greatest meaning but in frontal plane it is endurance and strength.
3. Restitution of none of the analyzed values of body posture features was not complete after 1 and 2 min. when carrying on the left or right shoulder was terminated, which means low overall fitness and immature corrective-compensatory processes.

Key words:
children’s health, moiré topography, physical fitness, postural asymmetry factor