To bare or not to bare your feet? Proponents of the former argue that humans have been running barefoot for millions of years.
To be precise, the Homo erectus (upright man) species did so about two million years ago, according to anthropologists, said
Mr Bernard Liew, a physiotherapist at the Changi Sports Medicine Centre at Changi General Hospital.
Some experts think the beginning of the end of the "barefoot era" occurred about 30,000 years ago, when footwear began to be used routinely to protect the feet against acute injuries, he said.
Eventually, what one had on the feet evolved into a symbol of cultural status - things have not changed that much after all.
However, in the arena of running, a trend has been evolving with an increasing number of runners reverting to running barefoot or wearing minimalist shoes.
The latter are shoes designed to protect feet from stones, nails, glass and needles but with minimal support to mimic running without shoes.
Fans of barefoot running say the sensory feedback helps them run better and that the wearing of traditional running shoes hinders their natural stride and is the cause of pain and injuries.
Research from as early as the 1980s has shown that the sensory feedback from the feet during barefoot running increases the flexibility and the ability of the feet to react and absorb shock when they come in contact with the ground, said Mr Ray Loh, an exercise physiologist at the Sports Medicine and Surgery Clinic at Tan Tock Seng Hospital.
SHOES REDUCE AWARENESS
Proponents of this style of running say it prevents injuries.
"The research on this has found that the sensory feedback is greatly reduced by the insulating sole (cushion) of the running shoe as it reduces the awareness of our foot positions," said Mr Loh.
The biomechanics of running show that every step that runners make produces a sudden impact force of about 21/2 times the weight of the body onto the legs.
It is hypothesised that this impact is the basic element which causes running-related injuries, said Mr Loh.
Research also suggests that modern padded running shoes modify the way individuals propel themselves forward during running because of a raised cushioned heel of around 8 to 12mm.
"The elevated heel has been said to lead to the shortening of the Achilles tendon and calf muscles, which interferes with pronation (the way the foot rolls inwards when you walk and run) and the efficiency of propulsion (forward push-off)," said Mr Loh.
Or, as Dr Irene Davis, professor of physical medicine and rehabilitation at Harvard Medical School and director of the Spaulding National Running Center in the United States, explained in a WebMD magazine feature: "We've over-supported our feet in running shoes to the point that our foot doesn't have to do what it's designed to do."
This means the feet muscles do not have to work as hard in running shoes and, when the muscles do not have to work as hard, they get weak.
A 2010 study published in the journal Nature found that runners who wear shoes tend to strike the ground with the heels of their feet first.
This is referred to as a heel-strike.
It generates a force of up to three times the body's weight, which can lead to injuries such as stress fractures and Achilles tendinitis (inflammation of the Achilles tendon, causing pain in the back of the heel).
In contrast, barefoot runners land on the balls of their feet, generating less impact when their feet strike the ground.
NO PROOF BARE IS BETTER
But is it really better for everyone to revert to the barefoot running of our ancestors from millions of years ago? Does it really prevent injuries?
Multiple studies presented last month at the annual meeting of the American College of Sports Medicine in Indianapolis in the US found that there were no significant benefits, in terms of economy of energy used, from switching to minimalist, barefoot-style footwear.
There was also no evidence that it prevents injury better.
According to scientists, if foot muscles do become more taut and firmer with barefoot running, people's arches should consequently grow higher.
But in a study presented at the sports medicine meeting, no changes in arch height were found among a group of runners who wore minimalist shoes for 10 weeks.
Mr Loh said that it is rare to see elite distance runners going it barefoot.
"There is still not enough evidence to show that barefoot running can actually prevent injury and improve performance," he said.
GOOD FOR LEG STRENGTH
However, it does seem to be a good training tool for improving lower leg strength and running posture, he added.
The sensory feedback allows more muscles to be activated to stabilise the feet. The light weight of running with minimalist shoes or no shoes, with low or no heel elevation, allows more time for the leg to return and land beneath the body, improving posture, he said.
Mr Liew said he commonly asks his patients to switch shoes and tweak their running form when they have injuries.
This is simply to give them a break from running the way they did before, which might have led to their getting injured.
"This means that any change in shoes or running form is temporary till the point of recovery. The runners then return to whatever shoe or form they were using previously," he explained.
Mr Liew said it is not clear that barefoot or minimalist running will provide that breakthrough in injury prevention.
Whereas looking at one's overall running style can probably determine the likelihood of injury, he said.
And changing running styles is something people can do just as well with shoes as without.
"I often advise people to change if they feel like it; then if they hate it, ditch it," he said.
This story was first published in The Straits Times on July 4, 2013
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