We definitely want to maintain and increase our strength during the season. That can only be done with resistance training. Our starting pitchers, the day after they pitch, they perform a heavy leg day. On day 2 which is their bullpen day, they perform after they throw a upper body routine. Those two days alone will help arm strength.
Arm strength is the ability to throw the ball.
That is done by the total body, not just the arm. We really attack the legs, squats, lunges that work the quads and hamstring. And we do a lot of abdominal work to work the midsection. Day 3 would be a lighter leg day, at less intensity than Day 1. Day 5 is pitching day.