Are sprints or distance runs better for lean legs?

Answer 1

The original post was completely opposite.

Generally distance runners are leaner, and sprinters have large calves and quads. Sprinters need to have strong legs for powerful turnover and explosive starts.

Of course, your leg size isn't going to make or break you, its the rest of your body's conditioning that matters. You could improve your leg strength and sprint, or go with distance. First try out the different distances.