What began as an investigation of why muscles become sore after walking downhill has led to an innovative way to develop and maintain longer calf muscles in children who walk on their toes. PENNY FANNIN reports.
Bend and stretch, reach for the stars,
Here comes Jupiter, there goes Mars.
Bend and stretch, reach for the sky,
Stand on tip-e-toes, oh, so high.
Research officer Dr Paul Percival is helping children like 10-year-old Fiona lengthen their calves to improve the body's biomechanics.
When this song was sung on the Australian children's television program 'Romper Room', thousands of children watching at home mimicked the actions and stood on the tips of their toes as they stretched their arms towards the ceiling. While this exercise was merely a game, there have been thousands of Australian children over the years with a condition that causes them to walk on their toes.
Up to 10 per cent of children are so-called toe walkers. Why they walk on their toes is unclear, but it is known that the habit can cause hip and back problems later in life.
Researchers in Monash University's Centre for Biomedical Engineering have worked with staff in the physiotherapy department of Monash Medical Centre to devise exercises that lengthen the calf muscles of toe-walking children.
The exercises are calf-raises, where the children stand on an incline plane, go up onto their toes and then lower themselves using their calf muscles to control the downward movement. Although simple, the exercises have stemmed from complex investigations of muscle mechanics.
Professor David Morgan, a reader in the Department of Electrical and Computer Systems Engineering, has long investigated muscle mechanics and was intrigued that although walking uphill was tiring, it was walking downhill that caused muscle soreness the next day.
"This was because the downhill walking was lengthening the muscle," Professor Morgan says. "When walking downhill, the thigh muscles are used as brakes to slow you down, an action that causes the muscle to lengthen while generating tension."
Dr Paul Percival, a research officer in the department, and Ms Christine Blackburn, a paediatric physiotherapist at Monash Medical Centre, working in collaboration with Professor Morgan, used the information gleaned from the muscle mechanics studies to devise the calf muscle-lengthening exercises.
"The calf muscles of toe-walking children tend to progressively shorten as they grow, until they are unable to put their heels on the ground," Dr Percival says. "For them to walk with a heel strike, rather than on their toes, their calf muscles need to be lengthened."
Ms Blackburn has worked with close to 200 children who are idiopathic toe-walkers, a condition where patients appear to be neurologically normal but, from their first steps as a toddler, walk on their toes.
"Often there's a history of their parents or grandparents also being toe-walkers,"
Ms Blackburn says.
"There is a range of reasons why these children should be treated," she says. "Parents of toe-walkers have concerns that their children look different to other children and are often teased at school. But we are concerned that if the gait style is left untreated, muscles will become shortened and affect the body's biomechanics. There is reduced knee-swing in the walk of toe-walkers, leading to lower back pain, outset hips and feet that point out rather than forward."
Until now, there have been three major methods of treating idiopathic toe-walkers:
operate and lengthen the Achilles tendon to allow the children to bring the
take the muscle into the stretched position and then set the lower leg in a plaster cast for two to four weeks;
use Botulinum toxin A injections, a neurotoxin that temporarily deprives the muscle of its nerve supply so the children are unable to rise up on their toes.
According to Ms Blackburn, each of these treatments has drawbacks.
"The first option, which involves surgery, certainly increases the range of movement, but in the longer term it may well lead to even shorter muscle fibres,"
she says. "The second option, splinting via plaster casts, is invasive, expensive and leads to wasting of the muscle. The third, botulinum toxin, has limited effectiveness as it lasts only three to six months and acts by weakening, rather than directly lengthening, the calf muscle. We wanted a strategy for management that was less invasive."
A final option of doing nothing is sometimes practised in the belief that, as the child grows into adulthood, their body weight causes them to drop down onto their heels when walking.
For the past three years, Dr Percival has been training idiopathic toe-walkers in calf raising exercises. So far, 60 children aged between four and 15 years have taken part in the study.
"The children do 100 calf-raises a day, and then we measure how much the muscle has lengthened," he says.
This study is the first to track, over a number of years, the effectiveness of treatments for toe-walking.
The way a person walks is a product of messages the brain sends to the muscles of the lower limbs, Ms Blackburn says.
"For children who toe-walk, the brain is sending mistimed messages, so the walking pattern is changed. We need an intervention, such as the calf-raise exercises, of two to three years to keep calf muscles long while we retrain the brain to achieve walking with a normal, stable gait."
To date, the results of the study have indicated that the children have longer calf muscles, are able to place their heels on the floor, and walk with a normal heel strike, Dr Percival says.
"Although the results might take a few months - or even years - to show up, we are confident these children will continue walking with a normal heel strike."