Define proper training? If you mean for maximum explosiveness and speed? None. But they CAN'T because a full NBA game is a completely different animal in terms of cardiovascular endurance even with the media timeouts and such. Not to mention playing 4-5x per week leaves no room for recovering from intense or heavy workouts. I DO believe some train hard in the off-season in regards to working on becoming more explosive but in season that's virtually impossible IMO.
To further expound that's why you don't see a lot of NBA guys dunking like pro dunkers, even tho (IMO) guys like LaVine, DSJ, DJJ, etc all.have MORE athletic potential than alot of circuit guys.
So yes and no. I think way to many don't do enough strength work, even in season but there are some that busy their asses off-season to gain another level of athleticism and then try and hold on as much as they can in season. I can't remember who penned it but there was a cited article a few years ago where the average NBA player loses something like 12lbs over the course of the season. That would make it difficult to retain anything IMO.
Now, guys that don't play as much... Or outlying freak athletes...orrrrr those ones using steroids properly to help recovery... That is a different story.
So cliffs: for maximum vertical/speed? None. For the best compromise between that and playing the game for 40mins? Yes some.