yeah, no kidding. there are only 6, bub. sometimes it may look like 8, but it's only 6 (technically speaking).

I have no idea wtf you mean by 10. That's just odd.



OP: Mix it up a bit, like others have said. Try switching between running (not long runs, do shorter sprints) and swimming. Toss in some high-intensity rock climbing and jump-rope to mix things up even more. All of those can work great.