Changes

The calculation of pace is fairly simple, and I used Excel. If your timings vary from sample to sample, then you need to average them out. In my testing, I got exactly the same time for each sample which made things easier. I calculated the number of inches per second the belt was moving at by dividing the distance (12 inches) by the time (0.112 seconds), giving me 107 inches/second. This is then converted to miles/hour by dividing by 17.6, giving me 6.087 MPH. Sadly, my treadmill was set to 7.0 MPH, so it's a long way off!=Even Greater Accuracy=The accuracy of the approach above is limited by the frame rate. This can be offset somewhat by measuring several samples and averaging the result, but it still has some error. This error is because of the marker won't move exactly 12 inches in a given number of frames. An alternative is to measure how far the marker moves in a specified time. You can use the keynote via to simplify this. You need to have some known distance in the image that's close to the markers on your treadmill. If you draw a line in Kinovea you can use that for calibration. Simply noting how far the treadmill marker moves in a given number of frames and drawing a line between those distances will tell you how far the treadmill belt has moved in that time. Calculating the treadmill speed is then fairly trivial. You can actually go a little further, and have calculate the speed for you. If you track a marker using the instructions in [[High Speed Video]] Analysis Kinovea will display the horizontal velocity. You can even ask Kinovea to display a graph of the horizontal velocity against time, as shown below. However, this may give you some rather depressing information, is your treadmill belt may be varying in during different points of your foot strike.{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"|- valign="top"|[[File:Treadmill Calibration A.jpg|none|thumb|300px|]]|[[File:Treadmill Calibration B.jpg|none|thumb|300px|]]|[[File:Data analysis.png|none|thumb|300px|]]|}=Equivalent Treadmill Speed=A lot has been written about the difference in running on a treadmill from outside, and what the equivalent pace should be. It's commonly advised that the treadmill pace should be a little faster than outside, or the incline should be set to about 1%. Unfortunately, I've never seen any research to back up this idea, and it would be nice to see some analysis using oxygen consumption as a definition of intensity. It's unclear to me how to compensate for a treadmill belt that varies in speed during the foot strike, as this becomes a rather different running mechanic from running outside.