> A lot of the injury risk when mountain biking is reasonably easily mitigated by controlling your speed and walking the bike through terrain that's above your skill level. There was a report out of British Columbia a few months ago about injury rates, and they were high, but BC is also a major downhill trail region.

Yeah, with downhill biking, “controlling your speed” means making sure you go fast enough to land the jump on the intended downslope. Go too slow and you’ll land wrong.