Running

erm, it can. especially if it'd be the first time doing core stability stuff - I.e. targeting muscle groups not conditioned to being targeted. DOMS anywhere on race day would be a shitty way to start the race.

OK, googled DOMS and it appears I'm suffering a slight case of it today having ridden to work yesterday with a new higher gearing. I get the gist, I'm going to take it easy on the run up to race day.