For me it was going to be the latter, but it seems as if my new running shoes have sorted out my "injuries" caused by my old Responses.. so, I'll be out on the tarmac!
What: Out-back negative split run, second half run at or near race pace; probably about 4 miles total.
Why: Speedwork.
Last hard - Yesterday - only 5K but fast, and I suffered agonising stitch for the last 2Ks which added at least 3-4 minutes onto my time - grr!
Last rest: Day before yesterday.