so my son who just turned 15 and has done a modified weighted ball program in the past. 2 days of throwing the various weighted balls and then a bullpen on the 3rd day with regular ball. The typical exercises you see on driveline, reverse pickoff etc. they are on his youtube page. This yr we are just starting the free program that you can download on driveline. read it carefully, he emphasizes the rest, recovery, warmup and cool down a lot. my 15 yr old barely has time for that wants to go home etc. but I do think its an important part of the program.
Like Kyle says his program has a ramp up, the first couple of weeks are actually pretty light and the most strenuous part is the long toss portion, which is tough my son has no interest in putting air under the ball and wants to throw hard all the time, in fact yesterday he threw a ball right through the webbing of my 2 yr old barely used Rawling glove, snapped the laces right off.
One other thing i would add, my son does take regular pitching lessons, his coach's number 1 concern is arm action and throwing safely and he has certified my son as being a good candidate for weighted ball training due to having very good mechanics.
my freshman is touching 83 right now, did run and gun 88 with a baseball the other day at a lesson where his coach was trying to show him how his body organized when he just tried to throw as hard as he could, hoping to transfer that kind of intent to the mound. He is never sore after throwing, has no pain whatsoever can throw every day, we dont ice or run after throwing. We own a marc pro but he says he feels totally fine and never uses it after throwing, its collecting dust or he uses after lifiting weights on occasion. I will report back in about 8 weeks to see how it is going on the plan. The one thing i did notice though last time we used plan was a more consistent pitching motion, tighter spin, breaking ball and changeup much more effective with a lot more bite. seems like the arm path after throwing balls was much more efficient.