Warm-up:
Dynamic Stretching
1600m Easy Run w/4x100m Sprints
WOD:
AMRAP 20:
Back Extensions
400m Runs
Ring Rows
Post total number of rounds and reps per exercise to comments:
(Note: to determine the reps, complete as many reps as possible for the first set. Complete the same for each additional sets)
Cool-Down:
Static Stretching
SPD CrossFit 
4 rounds completed (35 Back Extensions and 9 Ring Rows)