High heels can permanently change the way women walk and put them at greater risk of strain injuries, scientists have determined.
Researchers in Australia found that regular outings in towering heels shorten the fibres in women's calf muscles and can change the position of joints and muscles in the feet.
While it does not take a bio-mechanic to reveal that sometimes women suffer for their shoes, the study, inspired by the sight of tottering women walking around the researchers' university campus, is the first to analyse the ongoing effects of high heels on the way people walk.
The study, published in the Journal of Applied Physiology, found that women who wore heels on a regular basis walked differently than others, even without their heels on, using shorter, more forceful strides. The muscles in the feet become fixed in a flexed position with the toes pointed, long after a pair of heels have been kicked off, researchers found.
Scientists at Griffith University in Queensland attached electrodes to the legs of nine women who regularly wore heels to analyse their muscle activity. The results were compared with those from a group of 10 women who rarely wore heels. The heel-wearers - who had all worn heels over five centimetres high for more than 40 hours a week for two years - were made to walk over a plate that gauged the forces generated by their footsteps 10 times with heels on, then 10 times without the heels.
The flexed position of the foot puts greater strain on the calves, shortening the fibres in the muscle. A heeled gait strains the muscles instead of the tendons, meaning that women who wear them to work everyday use up more energy when walking.
Neil J Cronin said he began the study after noticing women in high heels looking "uncomfortable and unstable" around his campus.
"In a person who wears heels most of her working week, the foot and leg positioning in heels becomes the new default position for the joints and the structures within," Dr Cronin said.
"Optimal muscle-tendon efficiency while walking occurs when the muscle stays approximately the same length while the tendon lengthens.
"When the tendon lengthens, it stores elastic energy and later returns it when the foot pushes off the ground."
Dr Cronin recommended women take a break from heels "once or twice" a week to reduce the risk of strain injury.