TorBear;315401 said:
Can you throw a curveball 60 feet at 80 mph? I doubt many can.
A lot of major league pitchers don't throw their curveballs 80 miles per hour. The more specific and quantitative these "difficult actions" get the more this discussion veers away from its initial premise. It's not hard to throw a football ten yards to a stationary target, but it is hard to throw a sideline pattern to the wide side of the field. It's not hard to throw a curveball, but it's hard to throw one at a given velocity - velocity isn't even the most important part of a good curveball.
The fact that very few people can do something doesn't mean that it's the most difficult "motor skill" in sports. I can throw a baseball just fine - some would even say I can do it well. I don't think throwing a baseball where I want to with a decent velocity is difficult at all. But I can't throw it 100 mph. No amount of practice or improvement in mechanics will allow me to do that.
When I think of a motor skill as it relates to sports, I think of a repeatable successful action in its most general terms. Throwing a strike, hitting a baseball, hitting a golf ball straight, making a jump shot, dribbling a ball, ground strokes or a serve in tennis, catching a pass, etc.