Hurt back

Started out alright:

3x (each into a 15 yrd sprint)
foot fire
foot fire left
foot fire right
backward left
backward right

4x
fall downs
scramble ups

REST

8x
10 MN climbers into 20 yrd shuttle

REST

6x
4 squat jumps into 15 yrd sprint

On these I hurt my back. I got hit hard this weekend and that ended up weakening it, and these just pushed it over the edge...