Welcome to Week 1 Day 4 from your Strong January 2022 Challenge workout calendar. This upper body and core workout focuses on the arms, back, and obliques. The equipment suggested for this workout is a medium set of dumbbells (between 8lbs-12lbs) and a heavy set of dumbbells (between 15lbs-20lbs). The weights you use may vary. Always use weights that work best for you and your fitness level!