Sorry Hennieman...
The functions of a shoe:
* Grip
* Peak shock absorbtion
* Storage of energy from impact returned at 'toe-off' increasing efficiency
Running barefoot:
* It was first pointed out in a 1987 paper that normally unshod humans don't suffer from overloading of the foot
* When walking, habitually unshod humans attempt to grip the ground with their toes
* When running, the medial arch flattens to reduce shock by storing energy in the (well-developed in habitually barefoot runners) foot muscles and via elastic stretching of ligaments.
* This shock absorbing behaviour is related to from 'sensations' from the sole of the foot - the runner does it sub-conciously to reduce discomfort
* Running with a thick soft sole stops the sole of the foot 'feeling' the ground and inhibits this natural shock-absorbing function.
* The authors recommended that runners run barefoot after a period of progressive adaptation.
* If a runner is unable to do this each day or cannot run barefoot for safety reasons, a less-yielding shoe should be worn to increase sensory feedback.
* Foot position error was shown to increase 107.5% in subjects wearing shoes compared to barefoot runners
* Shod runners could not distinguish between a flat surface and a 20deg slope (barefooters could)
* It was argued that the use of footwear was largely responsible for ankle injuries as it reduced input from sole of foot 'sensors'.
* Falling frequency inreases with increased sole thickness
* Falling frequency decreases with increased sole hardness
In summary, the authours recommend thin hard-soled shoes to improve stability.
The paper highlight a number of points - the active shock-absorbing function of the foot, rather than thinking of the foot as a 'passive falling object', and the importance of sensory feedback frm the sole of the foot.
Source: Norris, C.M. (1998) Sports Injuries: Diagnoses and Management, p.331-334, ISBN 0750628731
