I played baseball in college and my head coach was not only that, but also the strength and conditioning coach of the entire athletic program. He busted our asses good and it paid off. I went into school a frail, shaggy-haired, stoner-looking kid, and came out a buff, shaggy-haired, stoner-looking kid.
One workout that was particularly useful was the Kettle Bell Swing. A kettle bell is a round weight with a handle attached to it that can be used for curling or swinging. The workouts he had us do with a kettle bell were in a swinging motion. Now, back then I was more into getting my biceps and pecs into prime beach season-mode, but my coach kept me in line a little bit.
A Kettle Ball Swing is performed with two hands and will workout multiple major muscle groups like your shoulders, back, hips, glutes, and legs. Prop the kettle ball in between your legs and reach down, grabbing the handle with both hands. Lower your entire body closer to the ground while keeping your arms out in front of your body. Use your hips, and explode up swinging the kettle bell as high as your head, but with your arms fully extended. Do not swing above your head! When you have reached the appropriate height, let the bell swing back down and then with its momentum, swing it back to the previous position. Repeat up to 20x or until your muscles are fatigued.