Hi im 14, 5'7 128 lbs, ive been working out for about 6 months, mainly on my abs, but also on my arms pecs and shoulders. My shoulders are quite broad and my neck is not bad. But my arm improvement is minimal and my ab definition is very minimal. I do 3 sets of ten with weights varying from 10lbs to 25lbs. And i do about 200 crunchs. I work out 3 times a week for about an hour. How can I improve my ab definition and make my arms bigger? plz help thanx alot