Could I do it physically, right now? Probably. If I pushed myself hard enough, I may be able to. The swim and cycle I could do, for sure, but running-wise I am only just knocking on 13 miles, and a marathon right now, on its own, in all honesty, would be quite a feat. Those casual mornings of nailing a 20-miler before work I know are coming back, but to run that after the two activities (a 2.4-mile swim and 112-mile cycle), considering I haven’t run that distance for a good five months, is a lot.