This is another post in our series of Fitness Saturday exercises and workouts appropriate to women in the second half of life. Personal trainer Brooke Marrone, president and founder of Brooke Marrone Fitness, in New York City, is our fitness guru.

1. Start lying on your left side with your head propped up in your left hand or rested down on your left arm. You can keep your legs out straight and stacked or bend them in front of your body.

2. Grab a 2- to 3-lb. weight in your right hand and bend your elbow to a 90-degree angle. Keep your elbow tucked firmly into your side so that your palm is facing downward. Make sure to keep your shoulders stacked and down away from your ears.

3.  You can place a small hand towel under your arm to help maintain proper position. 

4. Slowly, without moving your elbow, rotate your hand out, moving the weight away from the floor toward your top hip. Make sure to keep your wrist straight throughout the exercise and your abdominals engaged.

5. Slowly lower the weight back down toward the floor and repeat.  

6. Try 2 sets of 12 to 15 reps on each side. Beginners can start by just holding a tennis ball or water bottle until they are ready to advance.

Muscles worked: External rotators of the shoulders.