This is a workout I never would have attempted in my early running days- but now that I am older I discovered that intervals with short recovery may be more beneficial and actually easier than hard tempo runs.
I do this on artificial turf just inside of lane one of a 5 lap per mile track, starting on curve number 4 and finishing where you would normally start on a 400 track (measured with a GPS). After each interval I jog the 100 meters or so back in just under 40 seconds and start again.
Looking back about one year ago (see this workout), the first time I did this my focus was not on the interval time, rather my overall average pace including recovery. I remember getting those recovery jogs down into the mid 30s brought the average pace down under 6:50 for more than 6 miles. Today my average was 6:55 for 5 total miles.
If you are looking for an alternative to long tempo runs or 800 meter repeats, I'd give the 400s a try, starting with 10-12 keeping the pace reasonable (5K effort), checking not only your splits but perhaps more important your average pace (you need a GPS!).