Racergirl

Kim,

I would focus on plyometric movements with body weight... like jumping squats, burpees and jumping lunges. I think that building lactic capacity through strength movements helps your body develop some ability to handle the anaerobic component of these power movements (that are required for mountainbiking) and lifting your body weight versus isolating one muscle groups will strengthen all of the small muscles that stabilize you during the pedal stroke or run stride. You will get more bang for your buck doing that stuff.