HIT focuses on training to muscular failure. You lift very heavy weights for fewer repetitions and aim to fail at the end of each set.
Circuit training is one of the best home fitness routines that you can do to get fast results at little cost. The exercises can all be done with no equipment. Some exercises need a partner, but this routine has 12 exercises that you can do at home, in the park or at the gym. Old school and very effective.