Back Care

A school bag is worn roughly 190 mornings a year by a body that is still growing. Almost every complaint about school bags — sore shoulders, a stiff neck, a child who walks leaning forward — comes down to one of four things: the bag is too big, it is too heavy, it is packed wrongly, or it is worn wrongly. All four are fixable, and three of them are free.

1. Weight — the 10% rule

The widely used guidance is that a loaded school bag should not exceed 10% of the child's body weight, and should not routinely exceed 15% under any circumstances. It is a rule of thumb rather than a clinical threshold, but it is a useful one because it scales with the child instead of with the bag.

Child's weight	Target maximum (10%)	Absolute ceiling (15%)
20 kg (approx. age 6)	2.0 kg	3.0 kg
28 kg (approx. age 8)	2.8 kg	4.2 kg
35 kg (approx. age 11)	3.5 kg	5.3 kg
45 kg (approx. age 13)	4.5 kg	6.8 kg
60 kg (approx. age 16)	6.0 kg	9.0 kg

Weigh the bag on bathroom scales one Monday morning. Most people are surprised. If it is over, the fix is usually a water bottle filled at school instead of at home, one textbook left in a locker, and a bag that is physically smaller so it cannot hold as much. This is why we publish the empty weight of all twenty-three models — a bag that starts 300 grams heavier has used up 10% of an eight-year-old's allowance before anything goes in it.

2. Size — measuring back length

Backpack fit is set by back length, not height and not age. Measure it in two minutes with a soft tape:

• Find the C7 vertebra

  Ask the child to tip their head forward. The bony lump that stands out most at the base of the neck is C7. That is the top of the measurement.

• Find the iliac crest

  Place your hands on the child's hips, thumbs pointing backwards, and find the top of the pelvis. The line between your thumbs is the bottom of the measurement.

• Measure the distance

  Down the line of the spine, C7 to the iliac crest line. That figure is the back length.

• Match it to the bag

  The bag's back panel should be no longer than the measurement. A backpack whose base sits more than about 5 cm below the top of the pelvis is too long, whatever the label says.

Back length	Suggested capacity	Models to look at
28–32 cm	8–10 litres	Kinderpak, LitePak XS
32–36 cm	12–14 litres	Minor, LitePak Small
36–41 cm	16–20 litres	Junior, LitePak Medium
41–45 cm	22–26 litres	SchoolPak, OmniPak, LitePak Large
45 cm and over	32–41 litres	Maxi, DuoPak

3. Packing — heaviest closest to the spine

Where the weight sits inside the bag changes how heavy it feels more than the weight itself does. A load held away from the back acts on a longer lever and pulls the shoulders backwards, which the child compensates for by leaning forward. The further from the spine, the worse the effect.

• Heaviest items against the back panel. Textbooks and laptops go in the compartment closest to the spine, spine-down, flat against the panel.
• Medium items next. Folders, pencil cases and lunch boxes in the middle.
• Light and awkward items outermost. Jumpers, gloves and PE kit at the front of the bag or in external pockets.
• Load high, not low. The centre of mass should sit between the shoulder blades, not below the waist.
• Fill the space or compress it. A half-empty bag lets the contents move. Use the side compression straps — every LitePak has them.
• Nothing hard against the spine. No lunch box corners, no water bottles lying flat in the back compartment.

This is why our backpacks carry a semi-rigid sheet behind the main compartment: it holds books flat and stops a ring binder corner pressing through the padding into the child's back.

4. Fitting — both straps, high on the back

• Both straps. Always. One strap loads one side of the spine and one shoulder. It is the single most damaging habit and the hardest to break — which is why a bag that fits properly and looks right is worth paying for.
• Tighten until the bag sits against the back. There should be no gap between the back panel and the child's back. If you can slide a hand in, it is too loose.
• Top of the bag near shoulder height; base above the top of the pelvis. A bag slung low over the backside is both uncomfortable and unstable.
• Use the sternum strap. It stops the shoulder straps sliding outwards off the shoulders. Set it about 3 cm below the collarbone and do it up firmly but not tightly.
• Use the hip belt if the bag has one. On the LitePak Large, Maxi and DuoPak the belt transfers roughly a third of the load onto the pelvis. It should sit on the top of the hip bones, not around the waist.
• Re-check the adjustment each term. Children grow; strap settings do not follow. Our backpacks have 8–12 cm of adjustment for exactly this reason.

5. Putting it on and taking it off

Lifting a heavy bag from the floor with a straight back and a twist is how most bag-related strains actually happen. Teach the child to put the bag on a chair or a low wall, face away from it, put one arm through, then the other, and stand up with bent knees. Coming off, reverse it — never swing a loaded bag off one shoulder.

When to consider a different type of bag

A backpack is the best choice for most children because it distributes load across both shoulders and the pelvis. But not always:

• Where the school does not permit backpacks, a satchel with a wide, padded, non-slip strap worn across the body is the next best option. Swap the shoulder it sits on daily.
• Where a full kit travels every day, a separate sports bag carried in the other hand is better than an overloaded backpack — or use the Maxi, which separates the two in one carry.
• Where a child has an existing back, neck or shoulder condition, follow the advice of their clinician over anything on this page.