Posted: 26/11/2013 at 19:03
How do you vary pace on a treadmill? - I use one for training occasionally at home, but I can't imagine trying to aim to get a good time on it - I have to decide beforehand what time I will get, set the speed and just keep on it. Pressing the "down" speed button a few times is just not the same as easing off for a few seconds to relieve a niggle, then getting back into it.
Parkrun a few times and that time will tumble drastically, plus I guess you don't really know how accurate your treadmill is, so you may already be faster than you think.
A 2:13 half means you should be capable of ~28 min 5K, probably a little less as the calculators tend to be overoptimistic at longer distances in my experience. You'll have already done a ~31 min 5K during your HM, maybe less if you tailed off towards the end!