The evolution of athletic shoes: Chuck Taylor high tops. The Oregon Waffle. Adidas S.L. 72s and 76s (had them!). Air Jordan’s. Shoes made specifically for tennis, volleyball, weightlifting, running, cheerleading, wrestling, etc. Now the funky-looking toe shoes such as the Adidas adiPURE Barefoot or Vibram Five Fingers. Imelda Marcos would be proud.
Regarding the toe shoes – and particularly the evolution of running shoes – we have, in a way, come full circle. The barefoot or almost barefoot rage has brought us to this point: run shod (with shoes) or unshod (barefoot)?
Much debate and research continues on the pros and cons of shod versus barefoot. Let’s take a peek at some of the research out there, especially on the issues of safety, running economy, running speed, and oxygen consumption (VO2).
A recent study by Hanson, et al. reported that running shod requires greater rates of oxygen consumption than running barefoot. Compared to running barefoot, they reported 2.0 % greater VO2 for running shod on a treadmill. This difference was not statistically significant on its own, which is overall consistent with the literature.
Only two of seven studies that have compared barefoot and shod running on treadmills have found a statistically significant difference in VO2. An original aspect of the Hanson study was they also compared shod and barefoot running over-ground. VO2 for shod running was 5.7 % greater than barefoot running. 5.7 % is the greatest difference in VO2 ever reported for barefoot versus shod running.
A study by Squadrone and Gallozzi discovered these facts:
- Ground contact time (in seconds) during barefoot running was significantly shorter than shod running (0.245 vs. 0.255).
- Stride length (in meters) was significantly lower when barefoot running (2.19 vs. 2.34).
- Stride frequency (in strides/minute) was significantly higher while barefoot (91.2 vs. 86.0). As a consequence, step time was significantly lower as compared to shod.
Another study compared shod versus barefoot running using 35 subjects who performed two bouts of 4 minutes at 3.33 meters per second on a treadmill dynamometer. Barefoot showed these results as compared to shod:
- Lower contact and flight time
- Lower passive peak force
- Higher braking and pushing impulses
- Higher pre-activation of calf muscles
It was concluded that when performed on a sufficient number of steps, barefoot running leads to a reduction of impact peak in order to reduce the high mechanical stress occurring during repetitive steps. This neural-mechanical adaptation could also enhance the storage and restitution of elastic energy in the ankle extensors.
Lieberman, et al. found that consistent barefoot endurance runners often land on the forefoot (forefoot strike) before bringing the heel down, but they sometimes land with a flat foot (mid-foot strike) or, even less, on the heel (rear-foot strike). On the other hand, consistent shod runners use a rear-foot strike landing, which is augmented by the cushioned heel of modern running shoes.
Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who forefoot strike generate smaller collision forces than shod rear-foot strikers. The difference is primarily due to a more plantar-flexed foot at landing and more ankle compliance during impact. This decreases the effective mass of the body when it collides with the ground. Fore- and mid-foot strike running gaits were probably more common when humans ran barefoot or in minimal shoes. This may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
Researchers at the University of Newcastle found there is no scientific evidence to support claims that specially designed running shoes help prevent injuries. They found there was no published research that showed 1) running shoes controlled how much the foot rolled in, and 2) elevated cushioned heels helped prevent injuries. In fact, some shoes are specially designed to make a person land on the heel, which is unnatural, and may impair balance and makes one prone to ankle strains, so acute injuries are also relevant.
Potential Benefits of Barefoot Running:1
- May strengthen the muscles, tendons and ligaments of the foot and allow one to develop a more natural gait.
- By removing the heel lift in most shoes, it will help stretch and strengthen the Achilles tendon and calf muscle which may reduce injuries, such as calf strains or Achilles tendinitis.
- Runners will learn to land on the forefoot rather then the heel. The heel strike during running was developed due to the excessive padding of running shoes, but research shows this isn't the most effective natural running stride. Landing on the heel causes unnecessary braking on every stride. The most efficient runners land on the mid-foot and keep their strides smooth and fluid. Landing on the forefoot also allows your arches to act as natural shock absorbers.
- It may improve balance and proprioception. Going barefoot activates the smaller muscles in the feet, ankles, legs, and hips that are responsible for better balance and coordination.
- Running barefoot helps one improve balance, but it also helps them stay grounded and connected with your environment. A person can learn to spread their toes and expand the foot while it becomes a more solid and connected base that supports all movements.
Potential Negatives of Barefoot Running:
- Going barefoot or wearing a minimal shoe can be quite a shock to the foot and require a slow adaptation phase. But that isn't the only concern about a shoeless workout.
- If you have no existing issues and no pain, do you really need to change anything?
- Running shod offers more protection from ground debris such as glass, nails, rocks, and thorns. Shoes also offer insulation in cold weather and protect the feet from frostbite in ice and snow.
- Because most runners are not used to going barefoot, unshod or a minimalist shoe will be a shock to the feet and thus muscles will initially feel overworked. In some people, this could lead to injuries such as Achilles tendonitis or calf strain when the conventional heel lift is removed from the shoes.
- The plantar surface (bottom) of the feet is normally soft and tender in most people. Eschewing a stiff-soled shoe may initially cause plantar pain - or in those more fragile - increase the risk of plantar fasciitis.
- It is inevitable that almost everyone who switches to barefoot or a minimal shoe or starts going shoeless will find themselves dealing with blisters for the first few weeks until calluses are formed.
Run unshod or shod? The jury is still out. If you choose to go barefoot – or don the funky toe shoes - start slow and be careful. If you want to go with high-tech running shoes, seek a professional for the proper fit.