A lot of people enjoy running. I confess that I am not one of them. But I still find the construction of my brother in law's running shoes interesting. And I have tried on running shoes and found them immensely comfortable. And that is, of course, the point. When running, one expects to be wearing shoes for a long period of time. This means that running shoes have to be durable and comfortable at the same time.

Early running shoes

Early running shoes were hardly ideal for serious athletes. While there were shoes made with soft rubber soles in the early 20th Century, they almost always wore out too soon to be of much use. Indeed, running shoes (sneakers) grew out of the plimsolls which were made in the 19th Century for those who worked on ships. When people began to see their use in running, shoes began evolving.

At first, though, even with the rubber soles available, many runners preferred leather soles for their sneakers. The soft rubber simply fell apart too easily for professionals. Running shoes for sprinters had kangaroo leather for the soles, and they were spiked slightly for traction. Marathon runners chose heavier shoes, with thick and stiff leather soles. But, even with advances introduced at the 1936 Olympics, it wasn't until nearly 30 years later that we saw the first truly modern running shoes.

Modern running shoes are born

In 1962, an orthopedic shoe company introduced a novel design adjustment to running shoes. A rubber wedge was placed in the back of the shoe, between the upper and the sole. This allowed for increased comfort, since it change the position of the foot while running. Then, not too many years later, a University of Oregon coach, Bill Bowerman, got serious about designing an ideal running shoe for his track athletes. Some of the changes he introduced included:

• Nylon uppers (as opposed to leather or canvas).
• Sole made from urethane (instead of straight rubber or leather).
• Waffle sole, resulting in better traction without the need for spikes.

Bowerman started the company Nike, and the innovations of that company led to the creation of the midsole. The midsole in running shoes is an extra layer of cushion that lies between the sole and the upper. It adds to the stability and comfort of the runner -- and eases pressure. (After all, when a runner strikes the ground with his or her foot, the pressure is equal to three time his or her weight.) Today, midsoles are made from silicone gel or from some other type of cushioning material.

Today, as well, there are running shoes that come with pumps. These pumps allow you to fill bladders in the shoe with air, creating a tighter fit. This can increase comfort and stability. And, manufacturers of running shoes are always coming up with ways to increase your natural ability to run, while at the same time providing comfort. Mesh, lacing schemes, air cushioning and different sole patterns for traction are just a few of the ways that technology is constantly improving the design of running shoes.