Is This possible?

[Perza]

Im sorry have you ever seen Tyson at 13??....14...15.....same build just a little younger and he got a little bigger every year.....Believe what you want

Well just tell me how you can build up muscles what u dont even use? i mean my arms don't grow up if i just walk if there is some article that he did pull ups or something then i believe but only push ups and dips no fucking way those moves don't stress biceps i know because i've been working 4-5 years in gym. thats why this is hard to understand