Treadmills provide a measurement of the distance covered in a workout, typically in either kilometers or miles. If your treadmill isn't displaying properly, modify the display to show the correct measurement. However, be aware that the distance measured may not correlate exactly to the distance you've actually run or walked.
Finding the Distance Measurement
Most treadmills provide a monitor that displays information about your workout. The largest window typically provides information about the intensity of the workout, using a bar graph accompanied by numbers that equate to the intensity. In addition, you typically see a clock, which either counts up or counts down your workout. The display also shows a measurement of the distance you've covered, which should display as miles.
Modifying the Display
If the display is showing kilometers, use your owner's manual to change the settings to miles. In most treadmills, this involves turning on the power, keeping the emergency key in place and using a pen or cotton swab to depress the calibration control beneath the underside of the display console. Once the display for measurement begins to blink, you use the speed or other up and down buttons to modify the display to miles.
However your treadmill displays distance, it is a reasonable, but not exact, measurement. You run differently on a treadmill, using your knees differently and powering through the run in a slightly modified way than when running on a track. In addition, a treadmill is typically about 40 meters short of each kilometer you run, equating to approximately 120 feet for every mile. While this is relatively insignificant, it may impact your workout if you have a specific road-race distance for which you are training.
When you work out on a treadmill, the mileage may be slightly off, but the intensity is not. Runners who run on a treadmill and run on a track exert the same amount of effort, whether running for distance or sprinting. A January 2007 study published in the "Journal of Sports Sciences," evaluated the performance and exertion levels of distance athletes and sprinters, concluding that the results from either location were statistically similar enough to make either location a valid testing location for evaluating performance.