Training Relative

Small box, high box.  Step or jump.  A lot of Crossfit is finding what's relative and appropriate for you to do.  There's ABSOLUTELY nothing to be discouraged about if you're using a low box to jump on, or have to step for any legitimate reason, what matters is that you are moving functionally.  There will always be someone jumping on a smaller or bigger box, what matters is that you are jumping.  And if you can't jump, step! 

Workout:

5 Rounds:
12 Weighted Hip Extension
12 Weighted Sit Ups

800 meter run
30 KBS (35/53lb)
15 box Jumps
400 meter run
15 russian KBS (53/70lb)
12 box jump overs
800 meter run
10 one-arm KBS (each arm 35/53lb)
9 burpee box jumps