Mikey, I've never tried throwing tires or swinging a sledge hammer, but it seems like doing so could wear out the shoulders or risk injuring them.
I think hill sprints, ladders, shuttle runs, etc are a good idea.
Believe it or not, my sledgehammer isn't that heavy. It's only around 10-15lbs and the main shoulder involvement is on the up swing, and when it crashed into the tire. I have arthritis in my right shoulder from a yard work accident, and it has actually gotten better with this movement. Beating my tire with the sledgehammer is not a mass workout. I use it interval style, and it's quite a core burner. I have a feeling that it might actually add a little power to my server with all the rotation I use.
I plan to simplify things to just sprinting, sledgehammering, and doing power cleans. I was wiped out in a good way after sprinting today. I had to take the workout inside because of rain. I was in my basement and sprinted back and forth a long a 16 foot wall until I was panting for air. I rested until my heart rate lowered, and blasted out some more. I didn't quit until my legs were like rubber. I started out doing it with a split step and a crossover step, but quickly abandoned it for just regular sprinting.
Crossfit does look great. I passed a crossfit gym and I saw the most fantastically fit women doing pullups from the rafters.
In some way, I see crossfit as the McDonald's of function fitness--- they didn't invent interval training or functional fitness, but they are the loudest voice.
