The back squat requires the structures of the lower body and core to work synergistically. Optimal performance requires an adequate range of motion at the ankles, hips, and knees; superior lower-body strength; and a tremendous amount of core stability.
For time: 21-15-9 Back Squats 9-7-5 Wall walks
Scaling: Reduce the loading to a moderately heavy BACK SQUAT for you. An option for a scaled wall walk is to start in a push-up position with the feet touching the wall. Then, move the feet up the wall while keeping the hands in place. Walk the hands 2-4 steps toward the wall. Then, walk the feet and hands back down, without sliding, to a plank, then bring the chest to the ground.
Intermediate option: For time: 21-15-9 BACK SQUAT 9-7-5 Scaled wall walks
Beginner option: For time: 21-15-9 BACK SQUATS 9-7-5 Bear crawls, 5 ft.