I had legs like those when training fulltime for Ironman. 30 plus hours per week. Incredibly low skinfolds - 27mm over 7 sites (or was it 8?). When you consider that includes you tummy, there wasn't more than 2 or 3mm anywhere else.
That said I got sick a fair bit and had to wear a wetsuit in the pool or I froze. Beat all the fatties I trained with at least.
Not quite as ripped now that I just run, but not far off.