About 2 months ago I came across a workout that required a medicine ball. It looks pretty simple so I went out and got a 8lbs Med Ball
The point of the workout was to help teach the body to shift its weight properly during your down swing. ( example: getting stuck on you back leg and your hips not properly rotating through my swing)
The workout is quite simple. I grab the med ball with both hand as if I was going to swing a golf club.(Stance and everything). I slowly practice a nice smooth swing about 5-8 times. Each time I rotate back and through my swing I focus on my hips firing at the proper moment. After that I then swing the med ball another 5-8 but this time I swing at about full speed. (don't let the med ball go! ). The whole point with the second set is feel yourself drive through the imaginary ball like you would in an actual round. I do this little workout about 3-4 times a week and I usually do two sets each time.
I can say that in the short amount of time that I have been doing this little workout at home I have picked up about an extra 10 yards and my shotsare much straighter.
Give it a try...let me know what you think