The Agony of De Feet

One of our readers wanted to know the scientific basis for our preference. His question was this:

“In the shop article (center supplement) it is stated twice that a wood shop floor is easier on the feet than concrete.  What property of wood would make this so?  I have heard this same argument about tile vs. wood for kitchen floors.  None of these materials is compressible under “foot” pounds” of load so how can feet know the difference?”

I’ve never heard anyone question this before, so I decided to investigate. Most of the information I found was anecdotal. Everyone knows that a wood floor is more comfortable, but there isn’t much information about why that is. As our reader suggests, the floor isn’t compressing when you step on it, so what makes the difference? So I went in search of the scientific principle behind the mountain of anecdotal evidence. One source I found was the Maple Flooring Manufacturers Association. Another was the Canadian Centre for Occupational Health and Safety. Here is what I learned:

When you take a step, there is a good deal of energy generated at the point of impact. What happens to this energy when the foot meets the floor makes all the difference. It can either be absorbed by the floor or absorbed by the body. Any energy that bounces off the floor surface and returns to the body,is felt as an impact. One step doesn’t have much effect, but the cumulative effect of many steps over time can lead to foot, knee, hip and back problems. Tapping yourself with a hammer lightly on the bottom of the foot once wouldn’t cause an injury, but repeated tapping all day long could.

If you think of the energy of the foot impact as similar to any other form of energy, like a sound wave, when it encounters something it will wither be absorbed or reflect. Sound waves don’t compress a material when they hit it, but the vibrations from that energy are absorbed and dissipated by the material. Send that same sound wave at a solid reflective material like concrete and it will bounce back at you.

The essentially hollow structure of wood allows it to absorb much of the energy generated when a step is taken, or even when you shift you weight from one foot to the other. Even though you aren’t compressing the wood, the energy is able to move through the structure of the wood floor. Concrete on the other hand absorbs very little of the energy, most of it is reflected back through the body. Wood as a flooring material possesses an excellent combination of characteristics that make it an ideal flooring material for basketball players, dancers and woodworkers.

We recently had a reader suggest gluing pieces of anti-fatigue mats to the soles of the shoes he wears in the shop. A better solution is a set of shock-absorbing insoles. A company from my home town came up with a great material for this called Sorbothane. They also have a lot of technical info on their site.

When you kick your feet up at the end of the day, you really should have one of these mugs. The only place in the universe to get them is from the Popular Woodworking Store where you can also get T-shirts, sweatshirts, and caps.

thanks for reading,

Robert W. Lang