Experts recommend that babies be encouraged to crawl more, in order to enhance their hand/eye co-ordination, balance and motor skills.
The study, conducted by Sally Goddard Blythe, director of the Institute for Neuro-Physiological Psychology in Chester, said that babies are confining them to baby seats, booster chairs and wooden floors and are spending less time on their stomachs, which is hampering their ability to crawl.
The research on the basic physical skills of 339 children aged five to six, found 48 per cent had immature balance and co-ordination.
Blythe said that the early movements, such as crawling, induced skills which had a direct role in a child's ability to read and write. "Children are spending more time in car seats, sitting in moulded baby chairs, using baby strollers," the Telegraph quoted her, as saying.
"The sleeping on the back campaign, while absolutely necessary, means there is less of a tendency to put babies on their stomachs when they are awake. Babies are getting less 'tummy time' than 25 or 30 years ago," she said.
She said that infants who were always placed in a sitting position risked not passing through important stages, such as learning head control and developing neck and upper body strength, which can lead to immaturity in balance, posture and the control of eye movement.
"The action of crawling first on the tummy, then on the hand and knees helps to link and integrate the baby's developing sense of balance," she said. "It also trains hand-eye coordination at just the visual distance he will use when he learns to read and write," she added.
Christine Macintyre, a former lecturer and honorary fellow of Edinburgh University, who has written many books on child development, also stressed crawling as a vital part of development. She said most children with handwriting difficulties and co-ordination problems never crawled.
"Parents think that a child who goes straight to walking is somehow advanced, but it is not ideal," she said. "The crawling movement of raising one hand and the opposite leg is very important. So often now babies are popped into car seats and not allowed to move around.
"Parents are trying to protect them from every single bump and bruise on wooden floors. Children need to be put on the floor or grass and allowed to roll over into the crawling position," she added.