In reply to iusedtoclimb:
a few exercises there.
I also do core exercises as I found when I slacked off from regular core exercises my core 'fatigues' when running long descents (2-3km continuous downhill with about 1000m height loss).
And i also do downhill hill reps as well as uphill hill reps (but not in the same training session) - varying lengths, steepness, time etc