Isometric exercise is defined as a "method of physical exercise in which one set of muscles are tensed, muscle to muscle, for a period of seconds, in opposition to another set of muscles, or to an immovable object" by Webster's College Dictionary. If you have a regular weight training program and are unable to find the time to complete your workout, isometric exercises can be added to your regular strength and weight training. They take only 8 to 10 seconds and no special equipment is required.

Pressing the palms together is one form of isometric exercise. This simple exercise will increase the strength and muscle in your arms. You can also stand in a doorway, holding your arms at thigh level. Press the back of your hands against the door frame. Another exercise is clasping your hands behind your back. When you push them against each other, you can feel your shoulder and arm muscles working. There are even some isometric exercises that work more than one muscle at once. Stand facing a wall and place you palms against it while contracting your stomach muscles, and push against the wall. This works the muscles in your arms and shoulders. All of these exercises should be repeated at least twice and only last for a few seconds.

Isometric exercises use muscle to muscle contraction to build strength and muscle. Isometrics can easily be added to regular weight training programs by pausing along the peak of the movement or close to the starting point of the exercise. Remember to hold each pose for 8 to 10 seconds to get the best results.