I graduated 4 weeks ago. I run quite quickly so was already up to 6k in the 30 mins and thought I would simply add a km each week to get up to 10k. I was fine up to 8k even at 5mins per km pace, I could run round and feel fine afterwards. But last week when I did 9k and this week when I did 10k it was slightly different. I could still do the run OK - not at 5mins per km pace as I was starting the run with other people and then running on ahead at about the halfway point - but I did 10k in 58:37 so OK considering the 1st half was at well over 6mins pace. And immediately afterwards I felt fine, really OK, not puffing too much and not aching or exhausted.
However 6 hours later I was feeling really tired and needed a nap (I am 53) and the next day I really knew I had done some hard physical exercise, feeling it in my hips & lower back (which I damaged falling of a horse in my 20s). So both last week and this I haven't run mid-week after the long run on Sunday, partly as I felt I needed longer to recover but equally because I couldn't face getting that knackered in the week.
What is going on here? Am I tired afterwards because I have built up to 10k too quickly? Or because 10k is just too far to do on a regular basis (ie more than once per week)? And am I right to miss the mid-week run(s) or would it help to do something shorter like 5k to keep my body used to running?
Apart from being a bit longer and a bit slower pace the 9 & 10k runs differed from the 7 & 8 k runs in that they were non-stop. I did run/walk/run intervals for the 7 & 8k runs. Could that be the deciding factor?
I look forward to your most erudite replies. Cheers, Chris L