Muscle hypertrophy involves an increase in size of
skeletal muscle through a growth in size of its component
cells. Two factors contribute to hypertrophy:
sarcoplasmic hypertrophy, which focuses more on increased muscle
glycogen storage; and
myofibrillar hypertrophy, which focuses more on increased myofibril size. However, neither happens in isolation, which is why top-level
bodybuilders and
strongman competitors do not differ greatly in muscle size and strength.