Practice SC - we call them brick sessions, duathletes call them races 
Not good emzap - hope it's short lived.
chickadeee - I'm the same with marathons in particular - just wanted to do one which turned into 'run sub 4.30' for my first and was followed by sub 4, sub 3.45 but unfortunately I'm a long way from a sub 3.30 and I fear age may be against me.
I do something similar postie but no idea whether it's actually any use beyond the fact that I run faster for a bit than I would otherwise have done.
30 minutes run with Grace, cold out but lovely and still, sky looked to be full of snow though nothing has fallen as yet.