How weightlifting affect muscle growth?

Weightlifting stimulates muscle growth, but only when they are strained to the limit.

Easier weight training exercises improve blood flow and muscle responses to nerve stimuli, but they actually do not increase muscle mass.

Only the extremely strained muscles will gives a "sign" to the body to redirect the normal production of proteins on them, which will increase muscle mass.

Muscle fibers multiply on the existing muscles. This is happening instead of increasing of number of cells that make up the muscles. However, maximum increasing limit of muscles is conditioned by genetic inheritance, for which is responsible miostatin hormone.

Since the beginning of lifting heavy weight, and the first signs of muscle growth, proceed about two months.