so one little secret I have not shared that Jim Cawley used to do is the hammer twist or french hammer twist. It is a dynamic core exercise that hits the obliques and the delts big time. Take a barbell and put one end on the floor in a corner and you hold the other end. Add a donut (45lbs) less or more - start light and then work up to heavy. grab the end of the BB with the weight and hold it in front of you then twist to your right. When the bar gets to about waist high snap it around to your left. Keep your arms straight so the end of the bar goes in an arc of up and around to the left. Here is where it gets interesting. As the weight approaches your waist height slow the weight and then snap it up and around to your right. Rinse and repeat. The result will be a dynamic and plyometric core workout that will add a fair amount of thickness to your obliques and give you the strength you need to finish the heavy weight for distance throw. Do sets of 3-5 one day a week. Also you will find that giving yourself a wide base (spread your legs) will help with the torqueing forces trying to pull you off your feet.
I cannot find a video of this on the web tho. Maybe master dickens can come over and we will do some so we can post.