Working out is not rocket science. If you put your body under stress by loading your muscles and demanding they work, it adapts. Your muscles get stronger, your body gets fitter. If you have a sandbag around (or even a bag of sand) and a ten pace corridor to move up and down in, you have yourself the makings of a class A workout. The Powerhouse workout is designed to be simple but effective. It stresses out all the major muscle groups, it adds quite the load, over time and it helps you work up a sweat.
Extra Credit: 30 seconds rest between sets.