Protect Your Knees And Feet When Running



Posted: Sunday, October 25, 2009

by
http://www.treadmill-world.com

If you are long-time runner, you know what running can do to your knees and feet. You can reduce or prevent further damage by using a treadmill. Treadmills provide cushioning that research has shown can reduce joint impact up to 15%

Researchers have broken down the running step into absorption and propulsion phases. In the absorption phase, your heel hits the ground. In the propulsion phase, your foot propels you forward. It turns out that, though the absorption phase typically lasts less than a tenth of a second, the load on your joints during this time increases to up to 80% of your body weight, a stress that is up to six times greater than in the propulsion phase.

Thus, new treadmills seek to give more cushioning in front part of the belt, where the feet hit in the absorption phase. Perhaps as importantly, the cushioning under the middle and rear portions of the tread belt is designed to provide a firm footing that allows the forward motion to occur with the runner's joints property aligned.

Treadmills can also reduce the amount of energy expended compared to running on hard surfaces. When running on a hard surface, a certain amount of effort is required, in both the absorption and propulsion phases. Absorption is aided by the quadriceps muscles of the upper leg, while propulsion is provided largely by the calves. The cushioning in treadmills can reduce this effort by the treadmill user exerting more effort with the larger quadriceps muscles, thus burning calories more efficiently.

Many brands of treadmill proclaim the superiority of their form of cushioning. Trade names further the impression that that company's cushioning is unique. It is difficult to determine the truth behind these claims, since manufacturers typically give few details on how their cushioning mechanisms actually work. Most of the cushioning devices provide an adjustment that allows the user to choose a level from rigid to soft. On more expensive machines, this adjustment can be made while using the machine. Users adjust this while off the machine on less expensive treadmills.

Virtually all cushioning systems tighten or loosen the tread belt by increasing or decreasing the tension of a form of spring that applies pressure against the underside of the belt. Several commentators have suggested that users adjust the tread belt tension to a level where they can feel the "give," but where their footing remains sure. This probably provides a good rule of thumb to allow for as many years of safe running as possible. .

1 Salem, G.J., Ward, S.R., and Lee, T.Q. (2000). Regulation of plantar-foot kinetics during exercises on step benches with markedly different structural properties. J Str Cond Res. 14(1): 26-31. 2 Nigg, B.M., Denoth, J., and Neukomm, P.A. (1981). Quantifying the load on the human body: challenges and a few ways to address them. In Biomechanics, Vol VIIB, eds. Morecki, A., Fidelus, K., Kedzior, K., and Wit, I. University Park Press. Baltimore, MD. 3 Hamill, J., Bates, B.T., and Holt, K.G. (1992). Timing of lower extremity joint actions during treadmill running. Med Sci Sports Exer. 24(7): 807-813.

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Robert Braun has been using, selling, and writing about treadmills for decades. For more information on treadmill workouts, see http://www.Treadmill-World.com
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