I always thought this may have been Peter Coe's most incredible innovation. You create a workout where you are building up lactic acid, but instead of resistance or flat you being forced by gavity to keep your turnover quicker than comfortable. You are put in a position to stimulate your hip flexors and turnover system in a way that you cant do on either flat or incline, which may have been the special ingredient to give Coe the "double kick" when he was healthy and in his prime. Look at the gear change at the end of the 84 Olympic Final -- devastating!!!
foomiler, thanks for the link to Coe running on the Rivelin Valley Road:
What is interesting about those 6x800's with short recovery is that he is running slightly downhill with a following breeze:
The session starts at an elevation of about 165m and drops to around 75m in just under 5k
On that day a warm south westerly helped him as it probably did on most of the other occasions over the previous 12-13 years.
Just think of that 12-13 years of doing that session?
I never tried this, but I think i would if coaching an elite.