Isometric exercise, also called static tension, is a muscle contraction without significant movement or alteration in the distance between the joint the muscle is attached to. You do not need any weights or other equipment for isometric exercises -- so you can easily do them at home, on the line at the grocery store or while at work.
Sit down or stand with your back straight. Place the palms of your hands against each other in front of your chest with your fingers facing upward. Push your hands against each other to get isometric contraction in your triceps brachii muscles. Hold for 10 seconds and repeat.
You will need a towel for this exercise. Sit down on a bench. Place the towel around your neck so that the ends are resting on your chest. Grasp the ends with your hands and begin pulling the towel toward the floor. Keep your feet on the floor and your back straight throughout the movement. Hold for 10 seconds and repeat.
Stand approximately a foot away and your back toward a wall. Reach behind you with your arms and place the palms of your hands against the wall. Begin to lean toward the wall while pushing yourself away with your hands. Keep your elbows locked throughout the exercise. Hold for 10 seconds and repeat as many times as you desire.
Isometric exercises like any muscle-strengthening exercises increase your muscle strength and mass. Expanded muscle mass will increase your metabolism and tone your body. Working your muscles will also help improve your posture. According to the "Activity Guidelines for Americans 2008," adults should do at least two muscle-strengthening activities every week.
For people who suffer from high blood pressure, remember to keep breathing while performing isometric exercises of any kind. Holding your breath while contracting your muscles will raise your blood pressure.