Does open vs Closed growth plates affect the way you should workout? Also, heard that some kids get a velocity jump after they're plates have closed, any truth to it?

I dont know about open vs. closed growth plates, but I can tell you this. I tore the growth plate in my shoulder last summer. It took 6 months of Rehab to get me back in game shape. However, after the the growth plate healed, I threw 4-5 mph harder. Hope that helps.

Just stay away from heavy weightlifting until your doctor says the plates have finished growing.