if building muscle is caused by microtears then how come we don’t get bruises from doing it?

Question

if building muscle is caused by microtears then how come we don’t get bruises from doing it?

In: Biology

Answer 1

As many hypertrophy-related studies, the conclusions about muscle microdamage and its relation to growth are fairly ambiguous, but suggest [little to no correlation between damage and hypertrophy](https://www.strongerbyscience.com/muscle-damage/). Perhaps microtears do somewhat contribute to protein synthesis signalling, but it seems as though hypertrophy occurs regardless of muscle damage.

That said, bruising doesn’t occur since no blood vessels rupture, these truly are microscopic damages. With actual muscle tears, [major blood vessel damage and bruising can occur](https://symmetry.physio/wp-content/uploads/2019/08/Pectoral.jpg).

**Actual ELI5: when muscles break during exercise, most of the time it’s tiny cracks. Bruises are caused by blood leaking, but this kind of damage doesn’t affect blood vessels unless it’s an actual injury.**