How to train if you want to gain mass
If you want to gain mass, you should focus on changing your activity level as well your as diet. But remember that not all sports will make you look more muscular. Some of them, like long-distance running or cycling are for people who have a majority of slow twitch muscles. These muscles can contract for a long period of time because they have a constant supply of oxygen. Cyclists or runners do not get tired very quickly, but notice that they also look rather slim and are not very fast at the start. The easiest way to gain mass is to develop your fast twitch muscles. Again, we can"t change our physiological features much, so you will see the results only if you were born with the majority of fast twitch muscles. Low twitch muscles can be strengthened through anaerobic exercise as well, but they will not grow much in this process. If you want to train them, you had better try doing more reps because it takes time for them to produce energy. You can train your fast pitch muscles by doing less reps. These muscles usually get tired very quickly. All energy that they produce is used at once, without any supplies of oxygen. This is why most bodybuilders do not lift weights for hours. It is enough for them to do a couple of reps daily to gain mass in a short period of time.