I hate to be the guy who says “how hard do I throw” but this one will be a little bit different. I have the ability to watch myself pitch frame by frame on my video camera, which isn’t just great for breaking down mechanics but I’m also hoping will help me find out how hard I throw. From comparing guys I know who throw 80-85 I am around the 80-82 mph range. But back on topic, does anyone know how long the average frame is in seconds? I’m hoping by figuring out the length of a frame and how many frames it takes from ball to hand I can more accurately figure out what speed I’m pitching, as well how off speed my off speed pitches really are. Any help would be greatly appreciated!
You can only derive a rough idea of your velocity using a normal video camera.
At 30 fps, which is standard for consumer video cameras, each frame is 0.033 sec in duration.
When you use video frames as a measuring tool, there is no way to be certain exactly when the true beginning of your event occurs within the first frame or when the true end of the event occurs within the last frame.
If your calculations are off from the true value by as little as 0.033 seconds, that doesn’t sound like much. However, a ball traveling at 80 mph will move 3.9 feet in 0.033 seconds. That is a lot of uncertainty.
Anyway, it’s pretty easy to take the video and perform the necessary calculations–but you do need to accurately measure the distance that the ball is being thrown (it’s never released 60’6" from the plate–usually around 54 - 55 feet from the plate).
Let’s say it takes 16 frames for the ball to move 55 ft from your release point to HP:
16 x 0.033 sec = 0.528 sec; 55ft/0.528 sec = 104 ft/sec;
104 ft/sec x 3600 sec/hr x 1/5280 ft/mi = 71 mph
If my uncertainty estimations are correct, the best way to think of this velocity calculation is: 71 mph (+/- 5 mph).
One further post script:
The velocity you measure using the video method is average velocity. Air resistance causes a 7 - 8 mph drop in velocity as the ball travels to the plate.
So, if your calculated average velocity came out to be 71 mph (as in the above example) then the ‘out-of-hand’ velocity (what radar guns usually measure) would be about 75 mph. It would cross HP at about 67 mph due to air resistance.