Certificate

Medical Opinion on children’s school backpack 

CHARLES UNIVERSITY IN PRAGUE 2nd Medical School

Department of Exercise Medicine

V Úvalu 84, 150 06 Praha 5 – Motol

 

Identified in the patent documentation under reference number DE 602 03 441 72 T2 2006.02.23.

 

The backpack under evaluation is designed for children of school age, which is one of the most significant stages in human growth and development. It involves the pre-pubertal, pubertal and post-pubertal periods. In this stage of life the nerve system development is completed, body organs undergo intensive and quick changes, but mainly the body itself grows while being formed. It is therefore necessary to take all these factors into account when choosing a children’s backpack. In this evaluation, we cannot avoid emphasising the region which is directly affected by carrying loads as a result of increased impact of gravitational force on load-carrying parts of the body. This mainly applies to the spinal column, pelvic girdle and lower limbs. Carrying loads increases the static load which leads to immediate effect on the development of bones and joints, especially their growth zones. The activities of cells increase significantly and the direction of their formation is determined. This is caused by the vertical pressures acting as a sort of barrier to which the growth zone responses by emphasising sideways growth.

 

Although carrying a backpack is nowhere near such severe overload, there still remains a danger of excessive local load, mainly in the spinal column and the shoulder girdle regions. Taking all the factors into account, we come to the conclusion that a backpack is currently an optimum means of carrying objects by children. For children, the load should never exceed 10% of their total weight. As seen from the medical point of view, carrying a backpack is convenient for the developing motor system of the child. When adhering to the optimum weight and proper position on the back, it activates the bone cells and, through appropriate form of static load, it can balance certain disproportion between static and dynamic stimuli. However, all the rules for loading of children must be observed, the load must not cause deflection of the spinal axis, the carried weight must not overload the supporting system and the weight must be evenly distributed to prevent one-sided overload.

 

The backpack in question has a convenient system of shoulder straps. Their width is sufficient, they are well-positioned, soft and elastic which significantly reduces the effects of pressure on the skin and tissues situated underneath. Relatively poor subcutaneous tissue in the region over the collar bone may be affected by unsuitable local weight pressing nerves and blood vessels. Many painful conditions, both directly in the pressed region and transferred and felt in the upper limb, neck or even head are originally caused by the pressure vectors from carrying loads. The possibility of quick adjustment of the strap length reduces the danger of uncontrolled movement of the backpack including its contents. During the test, when putting the backpack on in the proper position, we did not find any excessive movement of the backpack. Too slack adjustment of the straps causes improper contact of the back wall of the backpack and the back, which results in the danger of local overload in the contact zone. The material and netting in the back wall reduces the danger of high moisture from sweat, which might otherwise have a negative effect on the skin respiration. Textile material of the back part together with the shaped lining reduces the danger of pressure on the back region caused by the backpack contents. The shaping is adjusted to the physiological curve of the backbone axis. The polythene rain cover is also considered as an excellent accessory, as soaking with water may lead to a considerable increase in weight of the backpack and a change in the distribution of load. In view of the fact that the backpack is designed for school age children, we consider it correct to decide on its size so that all the above stated properties of the backpack can be utilized. The criteria must be the length, the shape of the body, the spinal axis inclination, body weight and the type of the child.

 

I consider the school backpack under evaluation as a perfect backpack for school age children whose motor system is under development. Its all positive properties can be utilized on the premise that the proper size is chosen, it is well adjusted and the carried weight is distributed correctly on the body.

 

In Prague on 28th Feb, 2007

prof.MUDr.Miroslav Kučera, Dr.Sc