10%

50%

90%

20%

Muscle size (i.e. cross-sectional area) along with the type and number of motor units activated

Neurological signal (intensity and frequency) from brain to muscle

Strength and point of tendon insertion and joint angle

Microscopic tears; Inflammatory

Contractions; Inhibitory

Stress; Cytokines

Tension; Neurological

Nutrition, especially protein intake

Recovery, especially rest and sleep

Hormones, especially thyroid

Progressive mechanical overboard, especially eccentric contractions

Muscle growth requires going to the gym and lifting weights

The body adapts to repeated demands so that movements performed regularly often do not produce enough stress to cause hypertrophy

Cytokines are released during everyday activities that inhibit muscle regeneration

The nervous system cannot respond by recruiting more muscle fibers to generate hypertrophy