Which type of school bag is best for your spine and shoulders? A physiotherapist gives his expert opinion

Yeung says in most cases backpacks are the best option, as long as they are not overloaded with stuff. “The double straps of a backpack help to evenly distribute the load on your shoulders.”

Compared to other bags, its design is less likely to cause the joint deformation, or scoliosis (a back problem where the spine curves to the side) to which young people are susceptible, as your spines are still actively developing.

However, carrying a too heavy backpack can give rise to health problems like spinal disc herniation – also known as a slipped disc – and cartilage wear and tear if you aren’t careful.

“Usually, to put a heavy backpack on, students bend their upper body forwards, as though they are bowing,” Yeung says. Repeated on a regular basis, this action can create great stress on the spine, so it’s important you don’t put too much in the bag.

Of all the different backpack designs available, Yeung says that the best ones are those with chest and waist straps.

“These additional straps help disperse the stress on your shoulder joints.”

Single-strap bags can be worn straight down the body on one shoulder or diagonally across the body. When they are worn on one shoulder, your body naturally leans the other way to balance itself and to take the pressure off your shoulder.

Yeung says this should be avoided as much as possible because “poor spinal posture can lead to scoliosis in the long run”. Wearing the strap across your body means the weight is better distributed, and you end up walking with a straighter back.

However, he adds, a bag’s load is still all placed on one shoulder when you use a single-strap bags. Using them regularly, he says, can “also pose health risks to the upper portion of the spine”.

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Tote bags put a lot of stress on your shoulder, and use of them over time can lead to your shoulders developing unevenly. If you always carry your bag on the same side, that shoulder can tense up, which might lead to the muscles on that side of your body becoming bigger over time. Wearing a bag on one shoulder all the time can also affect your soft tissues and harm your spine, Yeung adds.

If your bag has wheels, then you avoid putting extra weight on your shoulders and back, because all you have to do is pull your backpack along.

However, if you’re pulling a heavy bag all the time, you still put unnecessary strain on your shoulder and spine.

The action of pulling your bag, when repeated in the same direction, can result in scoliosis, Yeung says, which is why you should switch which arm is pulling the bag along. “This can reduce the asymmetry of muscle tension and vertebral rotation.”

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When considering which type of bag to use, Yeung says YP readers should consider the weight and how long you need to carry it.

“If you have to carry something heavy, use a wheeled school bag. Otherwise, opt for a backpack.”

He adds that tote bags or single-strap bags are fine but only for short-term use. “Long periods of posture asymmetry and stress imbalance should always be avoided.”