when we exercise, our heart beats hard and pushes the blood around the body very swiftly, and when this happens the oxygenated blood reaches to the muscles very quickly so the muscles work faster and that helps in the developing of muscles.
They get bigger, and are able to lift heavier loads. The negatives of this, is the more the muscle is worked the harder it is to retain flexibility.
It allows you to move.
No exercise causes your muscles to weaken and can cause weight gain and tiredness
Correlation between skeletal muscle alterations, cytokines and exercise capacity
exercise will stimulate the muscles of the intestinal walls for increased peristalsis
its can give you strong heart :) and give you a lot of energry hahaah
Some boys exercise and those muscles are more defined and some do not exercise. Any layer of fat over the muscles also hides their definition.
The long term effect of exercise is stronger muscles. With stronger muscles, your body won't tire as quickly as it used to.
Exercise tears the muscles (causing some pain). When the muscles heal, they become defined and (stronger due to the fact they know strenuous activity will occur).
Aerobic exercise positively affect your muscular system. The more you incorporate aerobic exercise, the more you tone your muscles, helping them become lean.
Muscles get their strength from exercise.
Obesity,
actually you need to have some protein in order to build up your muscles and you need exercise too.