Spot Toning and Muscle-Building Tips

10 Muscles That Are Hard to Sculpt

From stubborn muscles that just won’t pop to secret spots you didn’t know you should (or could) hit, we reveal how to train your body's trouble zones

Protect Your Shoulders

Rotator cuff injuries are not just for baseball players, and they may not always manifest as pain, says Cressey. "At least 34% of people have partial cuff tears," he says. "Over the age of 60, more than half of people have partial tears."

The partial tears may not be causing a lot of pain … yet. To strengthen the cuff and increase mobility to avoid more series injury, Cressey suggests a side-lying external rotation with 30-degree abduction. The abduction "makes the exercise a little easier on the rotator cuff," he says.

To do it, lie on your side with your head propped up on your bottom hand or on a foam roll. Hold a light dumbbell in your top hand and bend your elbow 90 degrees, so the weight is in front of your belly button, palm facing your body. Place a small towel under your top elbow to create the 30-degree abduction. In this position, while keeping your upper arm against your side, rotate the weight up until your palm faces forward, instead of towards your body. Return the weight to start, and repeat.