Introduction. The analysis of the pupil’s environment is a set of stressors in the field of human ecology consisting not only of the genetic factor but also of the epigenetic one. Material and methods. The study of body posture was carried out in a group of 65 pupils at the age of 7, using the mora projection method in the following eight positions: (four positions for the right-hand thrust and four for the left-hand thrust): 1- habitual posture, 2 - posture after pulling a container with school supplies with one hand for 10 minutes, 3 – one minute after removing the load, 4 - two minutes after removing the load. The measurement of physical fitness was performed using the Sekita test. Results. The significance of differences between measurement 1, 2, 3, and 4 was analysed to determine the restitution of the size of traits after loading and their correlation with physical fitness to examine the relationship with the studied differences. Conclusions. (1) After removing the load, statistically significant restitution occurred after the first and second minute. Restitution was incomplete. (2) In right-hand carriage by boys, endurance significantly correlated with restitution, and among girls it was additionally speed and agility. As regards girls, physical fitness revealed more frequent relationships with restitution. (3) In left-hand carriage by boys, after the first minute, restitution correlated with endurance, power, agility and overall physical fitness, and after two minutes, additionally with strength, while among girls with strength, power, and endurance. After two minutes, restitution correlated with speed and agility in addition to the abovementioned postural features. As far as girls are concerned, physical fitness more often correlated with restitution. (4) Due to incomplete restitution after one and two minutes, asymmetrical carriage is not recommended to children aged 7 years. Physical fitness demonstrated by children does not lead to full restitution of the examined postural features, which suggests its low level and immature correctional and compensational processes.