What you need:
An exercise mat and a pair of five- to 10-pound dumbbells. Choose a weight that challenges you while allowing you to complete 10 to 12 repetitions for two to three sets.

Before you begin:
Warm up for three minutes with a brisk walk or by stepping from side to side on the spot. Then, standing with your feet hip width apart and knees slightly bent, raise your arms out to your sides and gently squeeze your shoulder blades backwards toward each other. Isolate the movement in your mid-back, and avoid waving with your arms; your shoulders should move only an inch or so. Repeat for one minute.