In the 1970s, a thin rubber-soled pair of canvas shoes was good enough for most runners. Fast-forward a few decades and an elevated cushioned heel, strategically placed pockets of air and/or gel, foam-based insoles and built-in stabilizers are just some of the features of today's running shoes. Operating a billion-dollar industry, shoemakers justify all this technology, and the subsequent leap in price, by promising one thing - a reduced risk of injury.
Runners bought it - not just the shoes, but the claim that the extra cushioning and stability is protection against injury and, therefore, worth the money charged for the added technology.
Lately however, researchers have been questioning whether that expensive technology delivers. And whether a stripped-down pair of running shoes can reduce the risk of injury as well or better than ones pumped up with air, gel, rubber or foam.
"It is apparent that the ongoing use of pronation-control systems and elevated cushioned heels in running shoes is being challenged," said Craig Richards, lead author of a 2009 study published in the British Journal of Sports Medicine titled Is your prescription of distance running shoes evidence-based?
"We have identified several studies suggesting that these features either fail to achieve their desired purpose, or worse still, have the potential to cause harm. Also apparent is the absence of clinical data, which are required to rigorously evaluate the direct effect of each of these features on injury rates."
Richards goes on to state that while it's a given that impact stress can lead to injury, there is no proof that the shoe design on the market is a panacea for the injuries that runners incur. And since injury rates in the recreational runner are significant, with 37 to 56 per cent of recreational runners being injured at least once each year, one has to wonder what role shoes play in the determination of those injuries.
Interestingly enough, it's not just researchers who are asking the question. More and more runners are eschewing shoes altogether and going barefoot. Bringing the foot in contact with the ground has its benefits, say shoeless runners. Without the added cushioning, the foot reacts by changing its stride and landing mechanics to reduce impact naturally. It also forces the foot to work harder, which in turn makes it stronger than a foot that has been pampered with extra cushioning and stability.
Of course, there are some basic problems with running barefoot - a lack of protection from glass, rocks, and doggie-do, for starters. So, too, is the discomfort of hitting the pavement unshod for the first time, especially after years of swaddling your feet in cushioning so dense you forget what the road feels like.
Perhaps sensing a sea change, running-shoe manufacturers have found a middle ground. The newest shoe out on the market is somewhere between barefoot and pampered. It features a thinner outer sole, less arch support and no elevated heel. The shoe feels more flexible and lightweight than the full-featured version and offers more protection and a smidgen more support than no shoe at all.
The question then, is: What is the average runner supposed to do? Is it time to dump your favourite pair of kicks and try something new? Or is shoe design, like Richards suggests, more driven by those selling the shoes than those wearing the shoes?
David Pearsall is an associate professor in the department of kinesiology and physical education at McGill. His area of expertise is biomechanics with a particular interest in running. A runner himself, Pearsall says the trend toward a lighter, closer-to-the-ground model of shoe is not necessarily a bad thing, but then again, it may not be suitable for all runners.
"Where is the cut-off between too much cushioning and too little?" he asked. Pearsall says it's too simplistic to suggest that running shoes can prevent injuries. Most running injuries are caused by a combination of factors with shoes being only one of the variables that experts look at when evaluating the origin.
He also warns against jumping on the latest shoe-design bandwagon, which may or may not have much research and testing behind it. This is especially true among some of the smaller companies that don't have the research-and-design budget of the larger manufacturers. In those cases, the shoe's design features are simply copied from whatever the industry's leaders are selling.
So where does that leave the average runner looking for comfort, protection and performance in their footwear?
Richards and his team of researchers say that runners should be aware that there is no ideal shoe type, so be careful whose sales pitch you believe. They also suggest that if you've remained injury free, don't go changing your shoes for the sake of change. That being said, if you suffer from chronic injury maybe a new shoe with new features is a good idea.
Don't expect miracles from your shoes, Pearsall said. No shoe will protect you from injuries caused by poor training practices. Nor will shoes worn beyond their life expectancy provide the protection they offered out of the box.
The lesson learned here is to think twice before buying into the latest manufacturer-based design changes, which may or may not perform as advertised. No one knows your feet better than you do, so when it comes to running shoes the best choice is the one tested in your own lab.