Friday, January 26, 2007

Treadmill running

Bidwell posted a question about treadmill running on HMM. I got some good feedback from my answer so I figured I would share:

As far as how comparable in motion and mileage. Typically the faster you run on a treadmill the more longer your stride becomes when compared to running the pace over ground. A similar effect is found when running uphill and if your treadmill allows, down hill running too. The increases are not much, but as the pace increases dramatically you could lengthen your stride by as much as 10 percent especially running down hill. The increase in stride length will also decrease stride rate. Also, when running on a treadmill your legs have a different purpose than when running on the road. On the road your legs are moving you forward as they bear weight. On the treadmill the belt is moving your legs once weighted, so your legs are really just stabilizing your body. You are getting the workout because you are constantly moving your trail leg to in front of you to get it ready to be moved by the belt. This along with the difference in stride length and rate are not so good for your running mechanics, but if you are running for general fitness this should not be an issue.

As far as it feeling faster when running outside that is true. As stated above your stride rate decreases on a treadmill so run running outside you feel the leg turnover at a faster rate. Also, with every foot plant the belt will slow down a skosh. At the point that your entire body weight is over your foot, the load on the motor increases and unfortunately the belt will slow until the motor catches up, which happens once all your weight is no longer on the belt. So, while the machine says you are going 10mph or 6 min/mile (just for easy math purposes) since the belt slows down at each foot plant, you are not really running a 6 minute mile. Obviously if you are running a 6 minute mile outside, that is what you are really doing. To avoid this, the higher continuous duty HP motor your treadmill has the better (at the minimum 2 HP). This will decrease the amount the belt slows each time the load increases on the motor. Some higher end treadmills have electronics in them that sense higher resistance loads and patterns and will pulse the motor to put out more horse power so that the belt is more likely to maintain a constant speed when running on it.


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