pull downs, work your abs alot too with sit-ups, fly's work great its the same motion as pulling your bow just backwards and on your back. Lets see byron ferguson do a shot like that! If your strong and have endurance in your shoulders and tri-ceps you'll be good to go. Your tri-ceps when your left arm is extended is where the pressure is when it comes to holding your bow, your shoulder is what is keeping your bow string back, get those two buff and thats all you need with some abs. If you got strong stomach muscels that helps with a climber as well.