First day of work workout

Five rounds for time of:
Row 250 meters
135 pound Front squat, 10 reps
15 GHD Sit-ups
20 Box jumps, 24 inch box

Subbed:
Run 2 sets of stairs down and up
115 FS
Anchored Situps
20" box

Got through first round in 3:30 and felt sharp back pain on the stairs and had to stop.
2 days later and just a little better.
No warm up and sat 6 hours prior to workout.