Balls - Triggers behind it

I always wondered how they made it so that the balls' distance affects how high they can fly. I don't know if you understand it, but it's basically how Baseball and Soccer was made on Warcraft 3. If you kick the ball HARD, the height of the ball goes really high then drops again. If you kick the ball WEAK, the height of the ball goes quite low and drops evenly.

What kind of triggers do this?

What map did you see this in?

The only ways I can think of are these:

One possible way would be using attacks as missiles and adding a differently arcing orb abilities (...if orbs have missile arcs...) or replacing the attacking unit to one with the proper arc depending on how far away the target is.

The other way would be to use flying units and changing flying height using some very advanced triggers depending on some sort of power of the launching unit and/or a random value generated when a projectile is launched... It'd be hard to make that one look smooth, though.

You could have a few different quadratic models for the equasion representing the ball. You could put the ball on the position related to the X and Y of the function. For harder hits, just have a more broad curve.

The creator of the baseball map left the map unlocked...
You can see the triggers from there