Mobilize, then:
A). 5×3 back squat (build to a comfortable heavy!)
B.) 21.1
For time: (15 min cap)
1 wall-walk
10 double unders
3 wall-walks
30 double unders
6 wall-walks
60 double unders
9 wall-walks
90 double unders
15 wall-walks
150 double unders
21 wall-walks
210 double unders