Changes

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 VideoAnalysis]] 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.