This week's workout comes from Ari at Lifetime. For those who want chiseled shoulders and a sculpted back, Ari suggests a new class call Upper Body RX. During the class, participants will use a heavy barbell or kettle bell, and then a moderate set of dumbbells for Olympic-style lifting in a group setting.

A 'clean and press' involves using momentum in your legs to help lift the barbell over your head. Ari recommends 12 reps of this move before grabbing a lighter set of weights. She says you can try a compound move that involves four exercises - a burpee, bicep curl, overhead press and overhead tricep extension - to round out your workout and work your core.