A study at Saarland University has shown: The warning against too heavy school bags cannot be scientifically justified. What puts a strain on children's backs is exclusively the wrong school furniture and hours of sitting. ELTERN online spoke to the human biologist and head of the study, Dr. Oliver Ludwig.
For years we got to read the message that the packed satchel must not be heavier than ten to twelve percent of the body weight in order to avoid irreparable damage to posture. How did you come to declare this warning absurd?
There is even the DIN standard 58124 on the subject of school bag weight, but even the experts at the Institute for Standardization in Berlin do not know where this value of ten percent of body weight comes from. Our research revealed that this recommendation apparently dates from before the First World War. It referred to how heavy a recruit's knapsack could be, so that long marches of 20 kilometers or more can be survived without symptoms of fatigue. Applying this value to school bags and ways to school is completely absurd. According to our research, there is also not a single piece of evidence that a child's back is damaged when they wear a heavier school bag.
But you sometimes see children who obviously have to carry a school bag that is too heavy. At least that can't be healthy for the shoulders!
What you are citing are children whose satchel straps are poorly adjusted. It is crucial that the satchel is worn correctly. If the belts are too long, the satchel hangs too low and pulls the child into the hollow back. In addition, such a wearing variant puts a strain on the shoulder blades. Of course, it is also unfavorable when children only carry their satchels over one shoulder. This rotation in the upper body puts a permanent strain on the spine. What we have often seen in our investigations: The satchels are packed incorrectly, that is, the heavy things were on the outer wall and not – as it would be right – close to the body. If the satchel is not worn properly, the child must constantly expend energy to keep the body in balance.
Heavy satchels are basically not a problem, provided they are worn correctly.
In our study, each satchel had an average weight that was 17.2 percent of the children's body weight, i.e. significantly heavier than the recommended ten percent. We let the children go a kind of exhausting way to school. The muscles were still not noticeably tired. A significant activity of the abdominal and lower back muscles was only measurable when the satchel weight was one third of the body weight. Only with this load did the spine change its position and the resting posture became unstable. Now the muscles also tensed significantly to stabilize the body. This relieved the spine. Our conclusion: A heavier satchel did not lead to significant signs of fatigue in the core muscles, even in the weaker and chubby children. A heavy satchel can even train the core muscles – at least for children who otherwise hardly have any movement. Since almost 50 percent of all children have such weak abdominal and back muscles that they cannot stay straight for the long term, any training to strengthen them must be welcome.
So the real problem is the lack of exercise?
Yes – and wrong school furniture! In children, the vertebral bodies are still growing and are very sensitive to one-sided stress such as sitting for hours. If a child sits bent forward repeatedly for a long time, the front sections of the vertebral bodies are primarily stressed. This stops their growth early at this point, but the vertebrae continue to grow behind. This creates a hunched back. This poor posture eventually turns into postural damage that can no longer be remedied. In secondary schools in particular, we see that children 150 centimeters tall sit in the same seating as children 175 centimeters tall. We have discussed far too much about school bag weights and far too little about topics such as "moving lessons" and "healthy school furniture". The children sit in school for eight hours and we worry about a 15-minute walk to school with a heavy satchel! But there are definitely progressive schools and committed teachers who show that something can be changed.
Sitting incorrectly is also said to impair the ability to learn.
We also carried out an investigation on this. We measured the blood flow to the upper body in a group of schoolchildren who were sitting on moving chairs and in a group who only had traditional seating furniture. There were drastic differences! After an hour in a conventional chair, there was a significant reduction in blood flow to the upper body – and thus probably also to the brain. Concentration problems should therefore come as no surprise. We look too much at pure orthopedics, i.e. muscles, bones and joints. But we should look at the whole body. Most of today's students will do their job sitting down. School is the place where young people could learn to use these sedentary activities in a way that keeps them healthy. Standing desks, short gymnastics during class or exercise offers for the breaks would be important. Far too little is being done here.
This article originally appeared on Eltern.de.