Progressive overload training is one of the most key aspects in hypertrophy and strength. Progressive overload is adapting to the progression from the previous workout into subsequent workouts. When exercising, the body creates a stimulus on the muscle that adapts when recovering and ensures that the muscles can handle the weight for the next session. The body performs are a cycle of creating a stimulus and then adapting. In order to achieve stronger and bigger muscles, the body needs to continue stimulating and adapting to stress thus creating an increase in muscle fiber size. Progressive overload creates stimulating reps that involve the stimulation of muscle fiber motor units at a high threshold. Heavy weight and maximal force causes this process. When continuing the same amount of weights or the same reps the recruitment of more motor units decreases causing less muscle stimulation. Progressive overloading means either increasing the weight or performing more reps with the same weight from the previous workout. Progressive overload training is essential for muscle growth long term because of the effect of muscle fiber size due to mechanical loading and stimulus.