To achieve rapid muscle growth without using steroids, it's important to focus on cutting down and getting lean before bulking up. This can naturally boost testosterone levels and improve muscle growth. Additionally, increasing training volume through a combination of reps and sets is a primary determiner of hypertrophy and muscle growth. Compound movements such as squats and deadlifts should also be included in your workout routine, targeting the muscle building triggers in your entire body. Aim for sets and reps in the 45 sets of 610 reps per set, and sleep and eat plenty of protein, carbs, and vegetables on training days. It's also important to slow down your lifts, as trying to lift heavy and fast can lead to poor form and less focus on the working muscles.