They do a million set of concentration curls per workout but my arms are still much bigger than theirs.
And I do only 5-6 sets of rows or pullups per session.
They train 3 hours while I am in and out of the gym within 50 mins(and that include changing,taking a quick shower,drinking my shake etc)
Often I go there,I see them doing bicep curls(and they look as if they have been training for some time liao)When I leave,they are still doing bicep curls.