Schools are being urged to consider the weight their students are obliged to carry given that a rucksack or backpack with 10lbs of weight will exert 72 pounds of force onto a student’s spine.
A research paper co-authored by spinal and orthopedic surgeon Dr Kenneth Hansraj and published in the journal Surgical Technology International found that the compression force on the spine was 7.2 times the weight of the backpack.
Furthermore, when the spine is tilted forward 20 degrees – common in those with already poor posture – the compression force is 11.6 times that of the backpack.
According to the paper, experts have traditionally recommended that the weight of backpacks do not exceed 10 per cent of the body weight of the carrier.
For an average 15-year-old weighing 56 kilograms, this would mean a backpack of six kilograms or 12 pounds. However, even this would exert 110 pounds of force onto a neutral spine and 143 pounds of force onto a spine tilted forward 20 degrees.
Dr Hansraj is warning that the persistent carrying of heavy loads can stress and inflame ligaments and muscles, leading to degeneration and pain. In severe and long-term cases, surgery may eventually be required to fix the problems.
He is urging schools and families to be careful with the contents of backpacks and to consider moving as much as possible to the use of digital textbooks.
Proper posture is also vital, he says, and students should adopt a neutral alignment – “ears above the shoulder, Angel Wings back, chest open”.
He said: “This is the most efficient position. This proper posture includes your chin being level with the floor, your scapula retracted, and your abdomen firm. Our study shows that in neutral alignment which is good posture, the forces on the spine are 7.2 times the weight. With just 20 degrees of forward posture (poor posture), the force is magnified to 11.6 times the weight. This is a 60 per cent increase in forces.”
Other advice includes:
- Wear both straps: The forces on the spine are the same with one strap or two straps. Both straps allow for a division of the forces that the spine sees. Similarly, with one strap, one side sees twice the amount of forces.
- Keep the backpack closest to the body: Closest to the body is the most efficient position for diminishing spine forces.
- Develop a strong core and legs: The body provides certain inherent muscle shock absorbers. Building the core muscles with for example planking helps to strengthen the body’s force dampeners. Strong thigh muscles help.