idk what timothy does. But I just find a spot in a field that is mostly dry hard dirt (i dont like killing plants) and then I beat the crap out of the ground as hard as i can with the sledgehammer. Switching arms as i go. I do this until I'm tired. Then I take a bit of a jog around the field. After I've rested up during my jog I do it again.
I also don't like gyms. There are too many people usually. The macho man attitude is just way to strong. Plus they cost money.
I'm interested to see what other ideas people have come up with for sledgehammers.