By LAURA ROBERTS
After a hard day in high heels even the most determined woman can struggle to keep a spring in her step.
But now it seems stiletto-wearers can strut their stuff without making their feet pay the price.
Designers at Marks & Spencer have fitted their highest heels with uniquely designed insoles so women don't have to choose between fashion and comfort.
The insoles are designed to shift weight away from the ball of the foot back to the heel - making women feel that the shoe they are wearing is much lower than it actually is.
The contoured inserts are placed under the heel and the arch to increase the stability of the foot and stop it moving forward in the shoe, which is said to improve posture and comfort - and stops toes from being crushed throughout the day.
It's the first time "Insolia technology" - insoles with built-in cushions - has been introduced to the fashion shoes in M&S.
The Spring 08 collection for Per Una, Autograph and Limited Collection will include 35 different designs with Insolia technology in heels over 4cm.
The man who came up with the Insolia concept is the world-renowned podiatrist Dr Howard Dananberg.
He says that a woman wearing a pair of 2in-high heels experiences 64 per cent more pressure in her forefoot than in a pair of flat shoes.
He claims this is reduced to 22 per cent when wearing the altered sole.
Celebrity osteopath and acupuncturist Garry Trainer, who has treated Gwyneth Paltrow, Jude Law, Sir Paul McCartney and Emma Thompson, said: "The ideal is always going to be an absolutely flat sole - or at the most a raised heel of half an inch.
"But pushing the weight back rather than forwards is an improvement as it makes the centre of gravity more stable.
"Women have twice as many arthritic knee problems as men due in part to wearing high heels.
"Prolonged wearing of high heels can lead to a shortening of the Achilles tendon, callouses, bunions and lower back pain as well as arthritic knees."
Pressure on the hips and knees increases by 25 per cent when women wear heels over two inches.
In the most serious cases high heels can even cause stress fractures to develop.
Health experts have even expressed fears that wearing heels excessively can lead to infertility.
In 1998, a team of researchers in the US linked high heels to knee osteoarthritis, a painful condition characterised by the breakdown of cartilage surrounding the knee.
Apr. 1, 2008