Free throw violation or not?

[Philz]

Smoke/Badnews......I can read and I did read it before I made this post but I thought I may have missed something in the rules...... as I stated I never see this happen in any college or NBA games I seen on TV and if its legal why wouldnt more players work on that timming as I think it would really improve your chances of getting the rebound....for those reasons only I question the rule....Can any big time college ref or coach answer this for me?

Does anyone else ever see this and do you call anything? This really isnt that uncommon especially in lower levels.

If its legal to get a running start towards the Basket and time yourself breaking the 3 point / free throw line extented plane legally why wouldnt you practice that and why I never see it in higher levels of Baskeball? Its really not that hard to time it. If 9 and 10 year olds can do why dont I see this in higher level of BB? If its legal you could actually start at the mid court point and with the ability of players now you could probably jump from the 3 point line an fly though the air and grab the rebound, as long as you didnt crash into anyone....right?