The same way any pro at that level has improved after training and competing for that long: an increase in drugs and perhaps some changes in training to bring up some weaknesses. At that level (in the 80s and 90s) most don't have glaring weakness, so the solution is drugs. These days, bags of smashed assholes earn IFBB cards, and the weaknesses are apparent, and notice how they remain (e.g., John Steadows, Rusty Handjob, Shelby Farms, etc.).
