Had the hardest run of my life yesterday in my Funday conditioning group training. We did the following:

Run 1 mile in 30 seconds run/30 sec walk
Partner - one partner runs 200 meters while the other does squats, ball slams and TRX rows - until another mile.

So 1.5 miles ran in total - and it was HARD! This was inside on the track - but I did it and really am not very sore today!