The weight of the schoolbag cannot exceed 15%.
The natural center of gravity of the human body is in the middle. If you plant your head upside down, it means that your center of gravity moves forward and you are hunchbacked. When a child's schoolbag is too heavy, his head will definitely lean forward in order to balance the situation that the center of gravity of the schoolbag falls backwards on his back. Over time, children get used to walking with their chests out.
Suggestion: The weight of students' schoolbags should not exceed 15% of their own weight. Children should form the good habit of sorting their schoolbags every day and take away books that are temporarily useless.
Three kinds of schoolbags are unhealthy.
One-shoulder backpacks from the sixties and seventies are now popular again. Straddling the schoolbag will stress one shoulder, resulting in uneven stress on the left and right shoulders. In addition, the weight of the book is not light, which will lead to shoulder and spine strain and even scoliosis in the long run. Similarly, children should not carry schoolbags with two shoulders to one shoulder.
In recent years, hand-pull-pull schoolbags have become popular. This kind of schoolbag, like a suitcase, has a pull rod and wheels, which can be towed away, liberating the child's shoulders but oppressing the wrist. This design makes the center of gravity of the schoolbag unstable, and it is easy for children to sprain their wrists when pulling.
The schoolbag in front carries the schoolbag in the back to the chest, which is a common way to recite in the street. The original intention of this back method is to prevent thieves. If the schoolbag is too heavy, leaning back and forth will only increase the waist load and increase the possibility of waist strain.