I would say JS has nothing to do with FT. It is a rarity to see a player who jumps on a free-throw attempt.
When you train FT it partially trains JS...
I'd like to address a whole other topic, speaking about things that need to be changed.I play this game since Season 7 (including some seasons in Germany II), and I'm still amazed about the famous "foul-gene". I see guards with fabulous outside defending, centers with wondrous inside defense... And looking at their stats I see 4 fouls, 6 fouls, 6 fouls, 5 fouls... It really bothers me, because come on... In the real world, nobody would consider a guy commiting an average of 5 fouls per 30minutes a fantastic defender.