Thanks for the info Pentaz. Anyway is it possible that i would get big arm muscle gains if i were doing only pull ups?

Pull ups will work your Lat muscles and biceps, thought i guess you cannot expect them being massive from that. Pull up as all self-weight strength exercises are great, even better than bb weight training, but you won't see such an great transformation in biceps, however you will see a change if that's what you're thinking :P

If you heavily do such exercises with self weight, you would train similar to gymnastic competitors so this is how they look:

[img width=700 height=511]http://www.gimnastika-cakovec.hr/admin/upload/filip_thnx.jpg” />
they are muscular and well built but not as nearly muscular as bbers. However their strengths are amazing, as well as coordination and their muscles are well trained to lift their own weight as if it was a paper.

I have very slim arms becouse i never did any serious workout or physical work more than couple of weeks. I have slim arms, slim legs but my torso is bit fatter. I look ok but realy i want to have a decent looking arms. Guy on the picture you posted is more muscular than i want to be. Anway if i strain my arms well they look quite good. Basicaly its not so much about being very muscular but desire to have more normal arm. Right now my arms are like this;

(note that this is not my arm but it looks very similar)

As for strenght well my strenght is quite good considering that i dont work out and how skinny my arms are. Its realy easy for me to do pull ups. I heard that skinny people should do more reps and less sets becouse we burn to much energy, they say that in gym we must try to lift as much as we can. Also some say skinny people should eat lots of calories. But i dont know if all this is true.