Back Squat 5RM / Wall Balls, Sit-ups, & DU’s Posted on August 22, 2013 by Matt FRIDAY 230813 Back squat 5RM – Work up in doubles and singles to your max weight for 5 reps. Attempt to increase from 160813. – Then – 10-20-30-40 reps for time of: Wall balls, 9/6kg Double unders Sit-ups Record results / post to comments.