Overview of Isometric Exercise

Isometric exercise is a type of muscle workout in which you perform isometric muscle contraction. An isometric muscle contraction occurs when your muscle exerts force without changing its length. In other words, when you do an isometric muscle contraction, your joint doesn't move. Unlike concentric (when the muscle shortens as it works) and eccentric (when the muscle lengthens when it works) types of contractions, isometric muscle contraction neither lengthens nor shortens the muscle fibers.

Pros and Cons of Isometric Muscle Contraction

There are pros and cons to doing isometric exercise. On the one hand, it is convenient. Isometric exercise requires no special equipment and very little time. But because the muscle fibers don't move during an isometric contraction, you won't get strong all the way throughout the muscle's range of motion. Strength gains are limited to specific spots related to the position you're in when you do the exercise.

Perhaps most important is that for people with high blood pressure (hypertension), isometric exercise is not a good idea. Isometric exercise has a tendency to increase your blood pressure.

Isometric muscle contraction may be useful when you're immobilized and/or healing, and you need to reduce your level of activity. If moving a part of your body would damage your joint in some way, your physical therapist or doctor may start you with isometrics. Isometrics are also used to help people who have been very inactive to get their muscle groups firing again.

Example

It's possible to strengthen the muscles at the back of your neck with isometric exercise: Start with your head and neck in vertical alignment with your trunk. Interlace your fingers and place your clasped hands behind your head. They should be placed at the bottom of your skull where it starts to curve down. With your hands, pull your head forward, but resist that force by pulling back with your head.

NOTE: If you have neck pain or an injury, be sure to talk to your health care provider before doing this isometric exercise.