The problem with fancy technology in shoes is that they make it difficult for the foot to function properly. The human foot is designed for motion, whether walking, running, squatting, or jumping. When there is a shoe on the foot that impedes upon the foot's natural motion, humans cannot move like we were designed to which leads to incorrect posture, suboptimal strength, movement efficiency, and flexibility.
One of the most common characteristics of the modern shoe is a heel lift, meaning the shoe is taller at the heel than it is at the ball. When standing still or in movement, having a heel in our shoes changes how our bones are stacked up which can cause postural problems. A raised heel also changes one's gait while in motion, causing the heel to touch the ground earlier than it would if there was no heel lift.
Another problem with many modern shoes that goes hand in hand with heel lift is excess padding. Some padding can be beneficial, especially if you are on your feet all day or going for a very long run. However, the amount of padding seen in the majority of today's shoes decreases one's ground feel and proprioception, which actually causes heavier footfalls. This can be experienced by conducting a simple experiment. Jump off of a chair onto the ground twice; once in padded shoes and once in bare feet. When jumping without shoes, we land much softer because we have better anticipation and feel for the ground. With padding, our internal suspension system does not work up to its full ability. Balance is also impaired with a built up shoe. This makes sense, as the higher you are off the ground the harder it is to balance. An extreme case is walking on stilts, and while traditional running shoes aren't five feet tall, they are high enough off the ground where stability becomes an issue. Softer surfaces also make balancing more difficult, evidenced by trying to balance on one foot on a mattress compared to trying to balance on one foot on a hardwood floor.
Arch support is one of the most common demands by shoe buyers. There is this belief that the arch needs to be held up by either an insert or the shoe itself. By allowing an insert or a shoe to hold the arch up, the foot's natural ability to function will slowly decrease to the point where the foot's muscles are atrophied and the natural arch is weak. If you let your foot's natural arch work instead of an arch support, the whole foot will be stronger for it.
Motion control shoes are similar to arch supports in that they both do work that the foot should be doing by itself. A roll bar or dual density midsole tries to stop the foot from turning inwards while in motion. First, it should be said that a bit of pronation is natural and completely eliminating all lateral movement causes an unnatural gait. Second, the foot will only weaken and lose its natural ability to control excessive pronation if the shoe does the work instead of the foot.
An area where the looks and function of shoes collide is the toe box. A wide toe box brings to mind clown shoes, and narrow toe boxes are generally seen as more stylish. This is unfortunate, as a narrow toe box will cram toes together, not allowing them to work properly and potentially messing up the function of the whole foot. People who have crammed their toes into high heels or dress shoes every day often times have very deformed feet with toes curling under each other. Unnaturally pointed feet not only negate the ability of the toes to function, but balance is also disadvantaged.
New technology in shoes appears to be all marketing and no research. The results of modern shoes speak for themselves: running injuries haven't gone down at all since the 1970's, which was when the running shoe boom got started. In fact, in one widely cited study those who wore expensive athletic shoes were more than twice as likely to sustain an injury than the people who wore cheap shoes.
Most modern shoes are deeply flawed in multiple ways. Luckily, good options do exist. A great shoe will have a wide toe box, zero height differential between the heel and the forefoot, no arch support or motion control, a flexible sole, and minimal padding. The only shoes I wear fit all of the above descriptions, and my feet are healthier because of it.
Thomas, Katie. "Running Shorts. Singlet. Shoes?" The New York Times. N.p., 03 Nov. 2010. Web. <http://www.nytimes.com/2010/11/03/sports/03barefoot.html?_r=1>.
Mcdougall, Christopher. "The Once and Future Way to Run." The New York Times, 06 Nov. 2011. Web. <http://www.nytimes.com/2011/11/06/magazine/running-christopher-mcdougall.html?pagewanted=all>.
Tougas, Damien. "What Does the Research Show? [Part 4 in The Case For Minimalist Footwear]." Toe Salad. N.p., 5 Oct. 2011. Web. <http://www.toesalad.com/the-case-for-minimalist-footwear/part-4-what-does-the-research-show>.