Lots of running

For time:
21 Hip-Back Extensions
Run 400 meters
18 Hip-Back Extensions
Run 400 meters
15 Hip-Back Extensions
Run 400 meters
12 Hip-Back Extensions
Run 400 meters
9 Hip-Back Extensions
Run 400 meters
6 Hip-Back Extensions
Run 400 meters
3 Hip-Back Extensions
Run 400 meters
14:29
I finished with the exact same time as one other runner who ran me down on the last 400m. I didn't realize he was as close as he was, but he worked hard to catch me at the end and we tied. This came down to running hard every round with an annoyance of back extensions each round. I felt my lower back by the third round, but it never really affected me, it just served as a break for each 400m. I forgot to time my first few 400m, but the splits were: 1.43, 1.49, 1.52, 1.47, 1.40. Only one round >1:50 and my last round picked up the pace even more. I am happy with the results, as I wanted to keep all rounds <2.00 for the runs. Afterward, I did 4 rounds of 5 hspu and 15 pullups with breaks as needed between exercises. I need to work on both grip fatigue and HSPU endurance.