I'm viewing this trail running thing as cross training. It's good for the leg muscles. After last night's experience, though, I'm thinking of revising that view. We ran from Constantia Nek "up to the reservoirs". I assumed they'd be part of the way up or something, and was assured by the organiser of the run that it was 9 or 9 and a half km.
An hour and a quarter later I was finished. It's a brutal climb straight up, then straight back down the same concrete road, so no real trail running, just plenty of pounding, and some admittedly fabulous views, accompanies by aching knees and a biting cold wind. Feeling sure that I'd worked harder than 9 km or so, I mapped it on Map My Run. It's 11.2km, with a 500m vertical climb. Bloody hell my legs are knackered.