By Dr. Mercola
Nearly 30 million Americans ran at least 50 times in 2012,1 signifying just how popular this exercise has become for fitness, sport, and simply as a pastime.
Yet, with the repetitive nature of the activity, along with the force of impact on your joints, bones, muscles, and tendons (up to five times your body weight) with each stride, the injury rate is high.
Research shows that the main risk factor increasing your risk of suffering a running-related injury is a previous injury in the last 12 months.2 Perhaps surprisingly if you've ever visited a sporting goods store and browsed at the row upon row of running shoe options… it had nothing to do with footwear.
This isn't what shoemakers, who claim their shoes can do everything from attenuate shock during impact to allow a smooth transition to midstance, and more, want you to believe… but could it be that your running shoes aren't as integral to injury prevention as you might have believed?
Vibram's Multi-Million Dollar Lawsuit
Bringing the issue of running shoes and injury prevention into the limelight is a recent $3.75-million settlement agreed to by Vibram, the maker of FiveFingers running shoes. The suit alleges that Vibram deceived consumers by claiming their glove-like shoes could reduce foot injuries and strengthen foot muscles.
While the company continues to deny any wrongdoing, they are allegedly agreeing to the settlement to "put the matter to rest and avoid any additional legal expenses."3 It's difficult to quantify the health benefits, or risks, of footwear because of the number of factors that come into play.
Age, gender, fitness level, experience, weight, prior injuries, and your unique running stride… all of these can influence your risk of a running-related injury. The Atlantic reported:4
"…the manner in which the body's muscles and nervous system respond to this impact [of running] is a critical determinant of stress to the body.
After all, the running stride is a wonderfully individualistic and intricate melding of foot, ankle, knee, hip, and upper body motion. Trying to control injury risk must always contend both with the complexity of the running stride and its inherent individuality in every runner."
So it may very well be unrealistic to think that a shoe could have significant impact, although that hasn't stopped manufacturers from trying. I wore a pair of Vibrams when they first came out, but they were very hard to put on and eventually caused me to have a fungal toenail infection so I gave them up.
Minimalist Shoes: Is Barefoot Better?
There's been a surge in interest in the benefits of barefoot running in recent years… or at least in wearing shoes that claim to be close to it. Sales of minimalist shoes increased 300 percent in 2012, compared to 19 percent for traditional running shoes.5
Surprising as it may sound, some research suggests modern running shoes, with their heavily cushioned, elevated heels, may actually encourage runners to strike the ground with their heel first—a move that generates a greater collision force with the ground, leading to an increased potential for injury.
Forefoot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may actually protect your feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners. Writing in the journal Nature, Harvard researchers explained:6
"Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes.
…habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe.
Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers."
This may explain how marathon runners in Kenya are able to run great distances barefoot with virtually no pain or injuries. Likewise, research reviewed by Michael Warburton, a physical therapist in Australia, revealed:7
- Running-related chronic injuries to bone and connective tissue in the legs are rare in developing countries, where most people are habitually barefooted
- Where barefoot and shod populations co-exist, as in Haiti, injury rates of the lower extremity are substantially higher in the shod population
- Wearing footwear actually increases the likelihood of ankle sprains, one of the most common sports injuries, because it either decreases your awareness of foot position or increases the twisting torque on your ankle during a stumble
- One of the most common chronic injuries in runners, plantar fasciitis (an inflammation of the ligament running along the sole of your foot), is rare in barefoot populations
- Running in bare feet reduces oxygen consumption by a few percent
You may know that I was a runner for over four decades and even ran a 2:50 marathon and won some local races. However, I have not run any long distances for over five years now. I still enjoy running shoes, though, and my favorite new ones are the minimalist Nike's Flyknit below, which really don't need laces at all. They are like light tight-fitting socks that conform to your leg and allow me to work with wood chips and not get any chips in my shoes.
Maximalist Running Shoes on the Rise, and Is Pronation a Bust?
At the other end of the spectrum are "maximalist" running shoes. These heavily cushioned shoes are lightweight yet feature thick cushioning often described as "plush" or "soft."
While some rave that they allow pain-free running, others prefer the minimalist option. Still other research suggested barefoot running used nearly 4 percent more energy with every step, which suggests it may be physiologically easier on your feet to wear lightweight – but not necessarily heavily cushioned -- shoes.8 So which is better? Barefoot? Lightweight? Heavily cushioned? It appears there may be no "right" answer. According to The Atlantic:9
"So do runners need align themselves as fervent believers of minimalism or maximalism? 'No,' [Brian Metzler, editor in chief of the running magazine Competitor] … told The Atlantic. Metzler says, 'I believe that a runner can have several different shoe types, each with a specific use.' Metzler believes the thicker cushioned maximalist shoes are more suitable for slower recovery runs, while light low to the ground shoes are better for faster workouts.
Carson Caprara, a senior product manager for Brooks Running, acknowledges that the difficulty with designing a shoe to reduce injury is trying to fit the unique characteristics of each runner, stating, 'That is why we have shifted our focus away from standardized baselines or a 'right way' to run, to using the individuality of runners as the starting point. The future of running shoe designs is designing a shoe that helps runners maintain their regular motion patterns.'"
Does Pronation Matter?
Pronation is the inward roll of your foot that occurs while you're running or walking. If you have normal or "medium" arches, you're a normal pronator (an inward roll of about 15 percent). But people with high arches are said to underpronate, while those with flat feet (or low arches) are said to overpronate. Different types of running shoes are now offered that cater to your personal pronation type, supposedly helping to prevent injuries, although new research suggests this may be a myth.
A study published in the British Journal of Sports Medicine revealed no significant differences in injury rates among runners with varying pronation wearing a neutral shoe. The researchers concluded, 10"The results of the present study contradict the widespread belief that moderate foot pronation is associated with an increased risk of injury among novice runners taking up running in a neutral running shoe. More work is needed to ascertain if highly pronated feet face a higher risk of injury than neutral feet."
Earlier research has also suggested that "prescribing in-shoe pronation control systems on the basis of foot type is overly simplistic and potentially injurious."11 As the New York Times reported:12
"In essence, what these findings suggest, says Rasmus Ostergaard Nielsen, a doctoral researcher at Aarhus University who led the new study, is that supposedly deviant degrees of pronation may not in practice be abnormal and do not contribute to injuries. And if that is the case, he continues, runners, especially those new to the activity, probably do not need to obsess about their foot type. Instead, he says, they could more profitably "pay attention to things like body mass, training, behavior, age and previous injury in order to prevent running-related injuries."
In short, it's clear there's still a lot we don't know about what type of footwear – if any at all – is best. There's a good chance that it will change depending on your activity, where you're running (on pavement versus a trail, for instance) and your experience level. Your best bet is to follow the principle of listening to your body and choosing the shoes that feel best to you. You will probably need to try on many different pairs before you find the right fit.
The Atlantic continued,13"'Part of the problem' says Jay Dicharry, a physical therapist and expert in biomechanical analysis, 'is the shoe industry as a whole does a really horrible job of matching footwear to feet… All the methods used to fit feet to shoes don't really hold up as valid ways to classify runners and to match shoes.'" If you want even more food for thought, there's also some evidence that long-distance running may be quite damaging to your health (so worrying about the type of shoe necessary to prevent injury may be putting the cart before the horse…).