Parents can tell whether their child’s school satchel is too heavy with a simple test, a German physiotherapist says.

Ask the child to balance on one leg when carrying the packed satchel. If they can manage this, it is unlikely the child’s back muscles will become overstrained, says Cornelia Goetz, who is based in the south-western German municipality of Breitnau.

She dismisses an old-fashioned rule of thumb practised by many parents that a packed schoolbag should not weigh more than 10 percent of the child’s body weight.

In fact, Goetz points out, healthy schoolboys and girls can carry satchels up to a third of their body weight with no problem.

In an age when children get too little exercise, that may be a good thing.

She advises against giving a child a trolley bag to haul schoolbooks. While the bags with wheels take a load off schoolchildren’s back and shoulders, pulling them can easily cause unnatural twisting of the hips and spine, she says.

- dpa