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Treadmill Detriments

This topic was first discussed in The Urban Caveman’s 13 Priorities as ‘Get Away From Exercising On Man-Made Surfaces.’ As stated in that article, the treadmill is basically a conveyor belt that masks propulsion and can create physical, biomechanical, and neural problems if used as a sole source of exercise. It is certainly a tool to use in your exercise arsenal for sprints and hills and such especially if terrain and agreeable weather are not available, but it should not be a chosen as a regular go-to exercise for results.

 

Another issue that plagues the treadmill, and is often used to validate it as a better option for exercise, is the Flexible Deck. The deck is the surface under the belt that manufacturers have the ability to allow stiffness or flexibility. Ask most people and even the manufacturers which is better and they will say ‘more flexibility’ or cushion. It is widely thought that more cushion, (or compliance), is better, but an analysis of the facts proves otherwise.

 

Ray Giannelli, vice president of engineering and development for Cybex states:

 

“The first thing that people should understand is that the maximum load developed during running is determined more by the kinematics and biomechanics of running and less by the surface on which they are running.”

 

In addition, regardless of the surface, (grass, dirt, concrete, treadmill), there was very little difference in peak loads and shock transmission on the body. The amazing thing is that runners are subconsciously able to adjust stiffness of their legs just prior to heel strike based on their perception of the hardness of the surface. How cool is that?

In addition, and contrary to popular belief, heel strike only imposes a force of 80% of bodyweight whereas during middle stride it is 200%. What this tells us is that it is the motion or mechanics of running form that is important, not the surface.

 

Taking it a step further, considering the forces at mid-stride and adding a deck that flexes as you are trying to create the force need to push off and propel yourself forward, increased time, distance, and force are needed in comparison to a rigid or stiff surface. Basically, you have to get out of the hole before you can get going. The detriments of an exercise can be measured by how long, how much, and how often force is repeated and enters the body. In the case of the treadmill, taking into account the time most people spend on it, the amount of strides taken in that time, and the extra force, altered mechanics, and disruption in timing of the gait cycle itself, one wonders the benefit of a flexible cushioning deck at all. Know also that when conditions of normal human movement change significantly, the risk of injury increases.

 

“As compliance (cushioning) of a treadmill surface increases you get to a point of diminishing returns with respect to reduction of shock. What you do get are other Biomechanical effects that decrease stability and change the timing of the muscle firing to the extent that the gait of the runner is now altered from a normal gait cycle.”

 

As a side note, although shoe manufactures apply cushioning to the soles of their shoes, they have, over the years, figured out that stability is much more important than cushioning. Stability is known to be more significant in injury reduction than cushioning.

 

-Leavitt 1.8.12