Exercises for your arms and back will become easier if you also focus on your shoulders, building strength and flexibility.

Without strong shoulder muscles, it can be difficult to properly execute even normal, everyday movements, let alone sports or other athletic activities. When your shoulders are flexible and strong, you'll have an easier time with things like lifting, pushing and pulling.

Shoulder exercises should involve all of the muscles associated with your shoulders, including the anterior deltoids, the lateral deltoids, the posterior deltoids and the supraspinatus (rotary cuff). These muscles work in unison to provide your shoulders with maximum elasticity.

One of the most popular shoulder exercises is the shoulder press, which can be executed either with dumbbells or with a barbell. Hold the bar(s) so that your hands are slightly shoulder-width apart in an overhand grip. Starting with the bar(s) at chest level, push up until your arms are nearly straight overhead, then lower them slowly again to chest height.

In a variation of the shoulder press exercise, hold a barbell behind your neck, then raise the bar slowly until your arms are nearly straight, lowering again. This focuses more on the anterior deltoids and should not be attempted without a spotter.

If you'd like to focus on the lateral deltoids, you might try the upright row in your regimen of shoulder exercises. With this movement, grasp a barbell or two dumbbells in an overhand grip, with your hands approximately shoulder-width apart. Then lift your hands until they are tucked just underneath your chin, and lower slowly back to waist-height. Your wrists will flex into a "puppy dog" position on the upswing of this movement.

And finally, for your rotary cuff, this shoulder exercise can be done either lying down or standing up, using one dumbbell at a time. When lying on your side, rest your head on your bottom hand, elbow extended above your head, and separate your legs so that the top ankle is about one foot behind the bottom ankle. Hold a dumbbell even with your hip, then slowly raise it until your hand is above your head. Lower slowly. For best results, concentrate on bringing your hand slightly behind your head on the upswing.

These shoulder exercises should make your more limber and supple in other exercises, and will increase both strength and flexibility.