The second one is
called myofibrillar hypertrophy and it represents enlargement of the muscle fiber as it gains more myofibrils, which contracts and does all the functional work — creates tension in the muscle.With this type of hypertrophy, the area density of myofibrils increases and there is a significantly greater ability to exert muscular strength.
Depending, whether you want to work on functional hypertrophy (also
called myofibrillar hypertrophy) or non-functional hypertrophy (sarcoplasmic hypertrophy), the work differs.
Step three — get stronger Muscles get bigger (a process
called myofibrillar hypertrophy) when they get stronger.