<b>What goes up must come down when it comes to footwear and now the vertiginous heels of the past few seasons have given way to pretty, practical flats. </b><i>Tracy Nesdoly</i><b> reports on the fashion world's economic indicator.</b> Form and function don't always follow suit when it comes to fashion, particularly when it comes to footwear. Trainer wearers or Birkenstock aficionados sometimes find that the tide of fashion has momentarily flowed towards them and their chosen shoe is suddenly at the cutting edge. However, for the most part, the shoes that set our hearts racing and our credit cards smoking are frivolous rather than utilitarian, while "comfortable shoes" are for smug marrieds and our mothers. Some of us have spent the past few years teetering around and keeping our balance despite treacherous pavements, while happily looking the world in the eye by virtue of vertiginous heels. For those days when comfort really is key, opt for a platform in which the ratio from heel to toe is less alarming to the knee joints. But what goes up, we suppose, must come down. Hence this season it appears the kitten heel has taken over from the cougar shoe. Stella McCartney showed off her mid-heel version in nude, which, we must admit, was still fairly sexy despite the demure proportions; Marc Jacobs showed bow-toed pumps, albeit with more heel than Stella; Rochas showed flat boots; and at Valentino, studs added a little toughness to the pointy-toed patent sweeties. Furthermore, Tamara Mellon, co-founder of the Jimmy Choo label, a brand known for its skyscraper party shoes, is said to be pining for her hi-tops, which are due to come out in May. Covetable flats at Jimmy Choo? There is no denying it, a sensible shoe revolution is under way. "There are fewer platforms and more lower heels around, which is good because women are becoming tired of running around in platforms," Erin Mullaney, the buying director for London-based Browns, told the fashion industry bible <i>Women's Wear Daily.</i> She especially pointed out McCartney's focus on the lower heel, which she said "felt dainty and feminine". It had to happen. Last season, Yves Saint Laurent had a deadly black bandage-wrapped stiletto, with a heel that resembled a shiny black patent pencil. It was gorgeous, tough, edgy and super-high, but utterly impossible, even for practised teeterers, to wear. Models quite literally fell off their platforms: Agyness Deyn tripped during Naomi Campbell's fundraiser fashion show for Haiti and, after a second tumble a few steps later, took off her Burberry platforms and proceeded barefoot. There was a bit of symmetry there - Naomi took a spectacular fall off 23cm Vivienne Westwood heels with a 10cm platform in 1993, when she was at the height of her supermodelling fame. Some models, most notably Abbey Lee Kershaw, refused to wear the "armadillo" alien shoes at the Alexander McQueen show last October. Kershaw said that "health and safety regulations have got to come into play at some point". So, while YSL was certainly not the only brand to push the limits, the end was clearly nigh. "There's no smoking gun unfortunately. There's nothing in particular we can point to which explains why trends in footwear happen," said Elizabeth Semmelhack, the senior curator at the Bata Shoe Museum in Toronto, one of the world's only museums dedicated solely to soles. "I do see, however, that times of economic stress bring more outrageous footwear - the 1930s for example saw the [return of the] platform for the first time since the 16th century." The platform in all its wild and wonderful forms, created by Elsa Schiaparelli or Salvatore Ferragamo, held firm until the stiletto took over in the more affluent 1950s. It was back during the oil crisis of the 1970s, and then again during the dotcom bust. So, if you're wondering where the economy is going, watch your feet. "However, why this occurs I really don't know," said Semmelhack. Having published <i>Heights Of Fashion: A History Of The Elevated Shoe </i>in December 2008, she's still not certain why females have recurrently gone for impossible shoes. The highest heels seem to be the uniform of times when women are not called upon to work outside the home - as in the 1950s when women returned to the home after manning the factories during the war years of the 1940s. Maybe the platform conforms to some desire for grounding during tumultuous times such as oil crises or economic failures. If that is the case, the current trend, where sanity seems to have grabbed us by the feet, may well be a very good sign and we might as well relax and save our soles for the next crisis.