The quest for speed

I've been told that speedwork is an important part of Marathon preperation especially in the early stages when you haven't started the really long runs. So today's intervals session was all about speed and being able to recover quickly from 400m of quick running. Unfortunately I didn't have the luxury of a 400m rest only 100 metres and it went soon. I managed 5 repetitions before I resorted to the easy jog to finish. Apparently I may doing 10 of these todays the end of training. I'm not sure I'm looking forward to that.....