Who Needs Isometric Exercise?

Isometric exercise strengthens muscles without lengthening or shortening muscle fibers and without moving joints. The muscle is tensed and held in one position. To build strength across the full range of motion of a joint, you would need to repeat the isometric exercise at every position throughout that range. Exercises are static, not dynamic, so they work best for recovering from injury and for conditioning, not for increasing explosive power or speed.

  1. Maintenance and Muscle Mass

    • Isometrics build muscle mass, so they are beloved by bodybuilders. The advantage to using isometrics is the ability to hold the stress on the muscle -- or muscles -- for a prolonged period of time. You measure an isometric exercise by time, not number of repetitions. During reps, stress on a muscle varies throughout the moves. But in static isometric holds, the stress remains constant. Submaximal isometric exercise stresses muscles without changing their length in static moves such as holding a weight steady, ideal for rehabilitating an injury. Maximal isometric exercise is also static but happens when you push against an immovable force or object, such as by pushing with your palms flat against a wall. NASA has used maximal isometric exercise to help astronauts counter the loss of muscle mass that occurs during prolonged stretches in a gravity-free environment.

    Muscle Stress Improves Yoga

    • Isometrics can safely increase the range of motion for joints in yoga poses. The contraction or stress of muscles held in a fixed joint position adds 15 degrees at either extreme of a joint's range of motion, according to Lauren Eirk, fitness director for Louisville Athletic Clubs, a certified yoga instructor and resistance trainer. A few isometrics before yoga practice could help you to go deeper into poses with a reduced risk of injury. Knees-to-chest hip flexion while supine and supine hip raises, which place stress on glutes and hamstrings while hip flexors are extended, strengthen hips, thighs and lower back. Contracting and holding core muscles builds strength in your essential midsection. Holding the opposing forces in a pose such as Downward-Facing Dog ultimately strengthens muscles and makes it easier to lengthen them into a deeper stretch in morning Sun Salutations.

    Planks and Pliés

    • Jazz, modern and hip-hop dancers need rock-solid abs to execute high kicks, isolations and hinges. Holding the plank position is pain with definite gain as the isometric value of the pose increases the longer you hold it. Try a classic plank, balanced on your bent forearms or flat palms and flexed toes, with a flat back and strongly engaged core. Time yourself and gradually work up to a five-minute plank. You'll see the results in effortless extensions and slow hinges that look as if you're floating on air. Isometric pliés begin with holding a turned-out second position for a few breaths. Progress to demi-plié and pause again before exhaling and rising as you engage the abs and contract the pelvic floor. Hold that contraction at the top of the move for three seconds before repeating plies four to six times. Isometric pliés contribute to a stronger turn-out.

    Portability and Precautions

    • Neglect your muscles by sitting in front of a screen for hours and you lose strength and tone. But your cubicle isn't the place for a weight bench, so practice a little stealth strengthening instead. Isometrics are easy to do at your desk. Seated leg extensions, with your tailbone against the back of your chair, strengthen calves and thighs. Overhead book presses strengthen your slumping shoulders. Compressing a resistant steel or plastic magic circle, also called a fitness ring, strengthens your arms, back, shoulders and chest. Isometric exercise provides a useful conditioning option, but it's not for everyone. If you have heart problems, high blood pressure or glaucoma, the sudden and sustained rise in blood pressure during isometrics could cause problems. See your doctor before adding isometrics to your fitness routine, and remember to breathe throughout the exercises to avoid unnecessarily high blood pressure.