Children should have their shoe size checked regularly
Four in five children could be wearing ill-fitting shoes that may cause them long-term damage, say experts.
The Glasgow Caledonian University found 83% of a random sample of children attending a local primary school were wearing shoes that were too small.
The Society of Chiropodists and Podiatrists has also found few parents regularly check that their child's shoes fit properly.
Both warn that, by not doing so, children could suffer unnecessarily.
Gordon Watt, consultant paediatric podiatrist at Glasgow Caledonian University, said the problems that could arise from ill-fitting shoes ranged from minor pressure marks and blisters to more worrying deformities and problems with gait and posture.
He explained: "Children are born with relatively soft and flexible cartilage, which gradually converts to bone with age.
"As they are growing, their feet are vulnerable to injury and deformity due to ill-fitting footwear."
Shoe fitting advice
Inspect children's feet regularly for inflamed nails, red pressure marks on the top of the small joints of the toes, below the ankle bones and at the back of the heel
Always have your child's feet measured for length and width
Inspect their shoes regularly for unusual wear. Seek professional advice if you are concerned
Avoid the use of plimsolls in school all day every day
Source: The Society of Chiropodists and Podiatrists
He said he had seen many children with knee and back pain caused by wearing the wrong-sized shoes.
He advised parents: "One of the most important things is to make sure that your child's feet are measured for length and width every time they get new shoes - even teenagers.
"Ideally, you should check whether your child's feet have grown and they need a bigger pair of shoes every eight weeks or so.
"Always have both feet measured, and the shoes should be 12-16mm longer than the longest toe."
Chloe, 13, had severe problems with pain in her knees.
She initially went to see her GP, who sent her to a hospital physiotherapist.
Despite 12 months of treatment her problem did not improve.
During this time her pain became so bad that she had to give up her favourite activities including long-distance running and netball.
It was not until her parents took Chloe to a chiropodist that it was discovered that it was one pair of ill-fitting shoes that were causing all the problems.
She has since thrown those shoes out, and her problems have disappeared.