Marshall began his training at the gym when he was around 20 years old. Before then, he would go to the gym, not know what he was doing there, and basically walk around and pick up a weight here and there. He didn’t have a clue. When he was 20, Marshall was introduced properly to fitness by a friend, who would take him and some other mates around. Marshall was guided by his friend through chest-days, leg-days, arm-days, and shoulder-days.