by KirkB » Thu Jun 18, 2009 3:10 am
If you know the speed of your vidcam (frames/sec) and you know the stride length of the vaulter, you can work out their speed on takeoff. You'll have to account for fractions of frames - since the frames aren't likely to both start and stop on an exact stride.
This works better for computing the average speed over the last few strides ... than the FINAL speed on the final step before takeoff.
An alternate way of using a vidcam to capture runway speed is to mark off 0, 5, 10, 15 meters from takeoff. Then you match up the frames to these marks ... instead of trying to match them up to any particular stride pattern. This allows you to compute the average speed between each mark.
Kirk
Run. Plant. Jump. Stretch. Whip. Extend. Fly. Clear. THERE IS NO TUCK!