A flexible sole allowed the boot to bend forward at the toe to allow the cross-country striding motion.

The company's boots, shoes and sandals are being reworked by the design director, Ralph Serna, in softer leathers and more flexible soles.

Hard shoes are made of black leather with flexible soles.

They usually have a canvas or cotton fabric upper and a flexible sole made of rope or rubber material moulded to look like rope.

They're usually made from soft leather or satin and have thin and flexible soles.

Liz Claiborne Shoes has a collection of ribbed "sweater boots" with flexible nonslip soles with treads.

The high lisle socks were also that special dark blue, but the high boots of tough but supple leather with flexible soles were sooty black.

Anticipating a rough climb into the ruins of Castledown, she had exchanged the sandals she normally favored for ankle boots with tough, flexible soles.

Debbie Dent, Trading Standards, says' the genuine sports trainers have rigid ankle support and flexible soles.

Additionally, athletic shoes with very flexible soles combined with cleats that "grab" the turf will cause overextension of the big toe.