Lower Your Incidence of Running Injuries
If you have been running for more than a few years, you have probably noticed how running outside has affected your their feet and knees. Running on a treadmill, instead of a running on a hard surface, can reduce the likelihood or severity of this damage with the cushioning that is built into most treadmills. Studies suggest that running on treadmills reduces joint impact up to 15% compared to running on harder surfaces.
Runners' steps have been observed to have two phases - absorption and propulsion. During the absorption phase, your heel hits the ground. During the propulsion phase, your foot propels you forward. Researchers have found 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. This is a stress that is up to six times greater than in the propulsion phase.
In order to provide more cushioning during the absorption phase, many of the better treadmills have more cushion in the front of the tread belt than in the back. 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.
Running on Treadmills
Running on treadmills can also require less energy than running on hard surfaces. 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. Cushioning can reduce this effort by on a treadmill by the user exerting more effort with the larger quadriceps muscles. This burns calories more efficiently.
Some treadmill manufacturers claim that their form of cushioning is superior. Their use of trade names furthers the impression that the company's cushioning is unique. That may be. However, 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. On less expensive machines, the user must make this adjustment while off the treadmill.
Seemingly all cushioning mechanisms tighten or loosen the tread belt by increasing or decreasing the tension on a form of spring. The spring applies pressure against the underside of the belt. Several commentators suggest that users adjust the tread belt tension to a level where they can feel the "give," but not past the point where their footing becomes unsure. This is a good rule of thumb to follow.
By Robert Braun