The truth of the matter is that running is a natural movement with which we have fallen out of touch. Over millions of years of evolution (in case you haven't been able to tell from past posts, I love evolutionary biology!), the environment selected for minor tweaks here and there to our bodies. As a result, we developed the ability to walk upright, freeing our arms to carry stuff (or pump to help us move our legs faster); an extremely complicated structure known as the foot; and a perfect arrangement of tendons, ligaments, and tissues that enabled us to walk or run whenever we needed to escape danger, hunt, move stuff, or have fun.
This is the barefoot runners' argument: evolution gave us a body that was not meant to wear shoes! Many indigenous tribes and communities around the world have maintained near-barefoot practices. The Tarahumara are a group of Mexican indians that lives off of ultra-distance running and booze, and they are virtually injury-free. McDougall's book (mentioned above) centers around this tribe of amazing athletes who insist on wearing no more than a piece of leather and straps.
While this is true, evolution never intended for us to walk around on uniform concrete all day long. The many bones in the foot enable it to adapt to uneven, rough terrain, meaning modern barefoot people - who wore shoes for the first 30 years of their lives - are probably doing more harm than good by diving into barefootedness.
Having said that, many people find that (slowly!) transitioning to barefoot running (or at least using as minimalistic a shoe as possible) helps them become not only a more efficient runner but also less prone to injury. The reason can be found if we look at the evolution of the running shoe:
1832 - Englishman Wait Webster patents a process wherever a thin, rubber sole can be attached to a canvas upper
1860 - A croquet shoe is developed using Webster's process. These shoes are noiseless when worn, hence "sneaker".
1890s - These shoes quickly began very popular as children's shoes.
1917 - The first popular sneaker is released in the U.S. The company is called "Keds", which is likely a combination of "Kids" + "peds". Also, Converse introduces it's high-top basketball shoe.
1964 - Phil Knight and Bill Bowerman found Blue Ribbon Sports. They begin selling Onitsuka Tiger shoes out of Knight's car at track meets. Onitsuka Tiger eventually becomes Asics. BRS eventually becomes Nike.
1974 - Bowerman experiments with waffle irons and creates the waffle sole. He markets a new shoes called the Waffle Racer.
After the introduction of the Waffle Racer, the running shoe industry exploded. Shoes became more complicated as time went on. Currently, it's nearly impossible to buy a regular running shoe without a big chunky rubber heel, which enables us to land on our heel with each step. To strike on the heel, you must lengthen your stride. Don't believe me? Try it yourself. Go find an empty sidewalk and take off your shoes. Walk a few paces, paying close attention to your feet. You will notice that your natural walking pace is programmed for a mid-foot strike, not a heel strike. Now, mark off about 20 yards on the sidewalk. Jog first with your shoes on between the markings, counting every stride. Repeat barefoot.
If you are indeed a heel-striker, you will count more paces during that drill barefoot than while wearing shoes. Without the plushy heel, we naturally correct our gait by shortening our stride, transitioning our body weight forward over the feet, and landing on the mid- or forefoot as opposed to the heel.
Mastering this technique will make you efficient without losing the running shoes. My buddy Dustin runs in Vibram Five Fingers occasionally, and, while he'll be the first to let the good vibes roll regarding minimalistic shoes, he confesses that the thin soles allow even the tiniest stone to jab into your plantar fascia. So I still like to wear my shoes. A longer stride is inefficient because it is often accompanied by locking out of the knee. When you land on a locked out knee, it acts to break your forward momentum. There's no fluidity to this motion, as you'll see in the video below:
The alternative is to lean slightly forward at the hips and allow your body to almost fall forward. Your feet are forced to shuffle forward in order to keep you from falling on your face. That's pretty much it! If you watch elite runners, their heels never hit the ground because they don't over stride. They land on their mid- or forefoot, and their cadence is very fast (90-98 strides with each foot per minute!)
Another benefit to running (or just walking around your house) barefoot is that it strengthens the many muscles in your feet. The 26 bones of the foot are controlled by a bunch of muscles that are required to do very little work from the day we begin walking due to our over-reliance on shoes. Allow your feet to breathe, and I think that you'll find that you'll be less prone to injury. Decreasing stride length = eliminating heel strike = lower impact running. By the way, flip-flops don't count! There's still a nice chunk of rubber under your foot!
My suggestions for improving your running are simple:
1) Slowly transition through very short distances if you wish to begin barefoot running. If nothing else, go to a high school football field and run a few lengths of the field without shoes on after your workout. Practice shortening your stride and landing mid- to forefoot.
2) Once you understand the basics, don't over think running. The beauty of the motion is that it should feel natural. As Matt Fitzgerald says, Run Unconscious!
3) Take your shoes off around the house and in your yard.
4) Aim for a higher cadence rather than a longer stride when you're trying to go faster. If you already are running with a high cadence, check out some of Joe Friel's writing (blog linked below) for drills to increase your stride length while maintaining mid- to forefoot striking.
Some more resources:
Send me questions if you got 'em: firstname.lastname@example.org