yeah ... like the man says (1) you should be able to do big weights on leg work with no problem ... here's a list
1) get a big weight and do squats, followed by tiptoe - REPEAT UNTIL YOU FALL OVER!
2) do mountain biking
3) do plyometrics (see other threads)
4) Judo is a good all-round muscle builder I believe
good luck
(2) works well I can vouch for