Adaptations During Heavy Resistance Training When it comes to heavy resistance training, achieving the desired adaptations takes more than the uninformed mind might think. By the conclusion of this article, the reader will have a better understanding of what adaptations involve during heavy resistance training; For example, the role of myosin, fiber types, cell structures, bone structures, muscle size, muscle shape, and the nervous system. Muscle size adaptations during heavy resistance training. Muscle hypertrophy is the growth of muscles. A common misconception when it comes to muscle size and growth, people think that their muscles grow over the duration of a single workout because they notice an increase in the size of the muscle they just trained. This is known as transient hypertrophy or "pump". Transient hypertrophy is the accumulation of fluids, from the blood plasma, in the intracellular and interstitial spaces of the muscle and lasts only a couple of hours at most. In contrast, chronic hypertrophy is an increase in muscle size over a long period of training with heavy loads ...