Cardio day with abs

Today's Crossfit WOD is:

Four rounds, each for time of:
800 meter run

Rest as needed between efforts.

I did it on the treadmill at a 1.0 incline.

My times were:
3:51
3:38
3:26
3:16

Rest was 1 minute between runs.

My pace was too slow. I should have done much better. Now I have a baseline for next time.

I also fried my abs and lower back.