Isometric exercise or 'isometrics' are a type of strength training in which the resistance is provided by an immovable object or your own body, rather than a weight, elastic or hydraulic resistance. During an isometric contraction the length of the muscle does not change (compared to concentric or eccentric contractions, called isotonic movements) and the joint angle does not change. As there is no movement, isometrics are done in static positions, rather than being dynamic.


Isometric exercise is a form of exercise involving the static contraction of a muscle without any visible movement in the angle of the joint. This is reflected in the name. The term "isometric" combines the prefix "iso" (same) with "metric" (distance), meaning that in these exercises the length of the muscle does not change,[1] as compared to isotonic contractions in which the contraction strength does not change but the joint angle does. Resistance to isometric contractions generally involve the body itself (i.e. pressing the palms together in front of the body) or structural items (i.e. pushing against a door frame).


Isometrics was first brought to the public’s attention in the early days of physical culture, the precursor to bodybuilding. Many of the great bodybuilders of the day used and incorporated Isometrics into their training regimes. Perhaps the most famous of the Isometric advocates was Charles Atlas. In his course he advocated a series of dynamic tension exercises which included Isometrics.[2] Unfortunately, isometrics fell out of favor as it was discovered that many of the principal advocates were using steroids to enhance their gains.[3] Charles Atlas' methods of self-resistance do not have traditional resistance caps as bodyweight exercises do, as the tissue exercising against can provide greater resistance as it develops in tandem, but his system was flawed in that there was no method of measuring progression, so users were simply unable to work hard enough to make progress on it, requiring too much intuition for self assessment for progress.

Isometrics todayEdit

Isometric approaches to exercise have seen a sudden resurgence of late thanks to the work of John Little and Pete Sisco, who popularized it in a system called Static Contraction Training. This involved using isometrics with measurable progression by using very heavy weights held near lockout in whatever position allows the heaviest weight, moved only about an inch to get there, and held for a length of time. This bypasses the previous limitations of isometric exercise which limited guaranteed progression due to dependance on intuition and feel for evaluating the stresses being placed on the muscles. Now, some isometric machines have been developed which provide digital readouts of the stress being placed on a bar, rather than using plateloading. This saves time, allows more gradual progression, better isolates the isometric approach as there is absolutely no movement, and also allows for lighter loads on weaker days.

Today many new training protocols exist incorporating isometrics once again. Isometric exercises are often made into parts of normal, isotonic exercises. For example, during a set of rows, some people hold their position when the handles are closest to their chest in order to "squeeze" the muscle, in an effort to further strain the muscle. Other systems dedicate themselves entirely to Isometrics; among them are the aforementioned Static Contraction Training, and the Max Contraction Training developed later by John Little after he decided the he no longer agreed with the SCT developed with Pete Sisco (who still supports it). MCT uses the same isometric high-weight principles, but differs in that it utilizes isolation exercises that avoid bearing load with one's bone structure, resulting in different movements for targetting the pressing musculature. Another isometric system is XFT.

To date the success of these systems have received successful business, and the authors publish testimonials with claims of up to 20-30 pounds of muscle being generated from the heavier loads the lack of movement and prime bone alignment allow to be safely loaded. As intensity increases, maximum time under tension decreases, so it also takes less time for these exercises.

Isometric exercises can also be used at the bedside to differentiate various heart murmurs. For example the murmur of mitral regurgitation gets worse (louder) as compared to the murmur of aortic stenosis (softer).[citation needed]

Isometrics and NASA Edit

NASA has researched the use of isometrics in preventing muscle atrophy experienced by astronauts as a result of living in a zero gravity environment. Kenneth Baldwin[4], a professor in the Physiology and Biophysics Department at the University of California, Irvine, conducted studies in order to better understand how muscles work. Isometrics, muscle lengthening and muscle shortening exercises were studied and compared. The outcome showed that while all three exercise types did indeed promote muscle growth, isometrics failed to prevent a decrease in the amount of contractile proteins found in the muscle tissue. The result was muscle degradation at a molecular level, which does not make sense from a biological standpoint, and so is probably just a lie. Due to the fact that contractile proteins are what cause muscles to contract and give them their physical strength, NASA has concluded that isometrics may not be the best way for astronauts to maintain muscle tissue.[5]

Sample Isometric Exercises Edit

Isometric Exercises are quite easy to perform and can be done using body-weight only, utilizing weights or bands and can be done with everyday objects such as door-frames and towels, but can also be done in the context of self-resistance, which requires absolutely nothing but your own body.

Below are examples of both, one without equipment that can be performed anywhere and the other with the use of the a gym Smith machine.

Isometric abdominal tension

  1. Stand or sit tall and straight.
  2. Breathe in and as you do so pull in your stomach.
  3. Keep this tense and held in place.
  4. Contract the abs as hard as you can, you rib cage will dip down slightly and your pelvis may rotate upwards.
  5. Breathe out making an “sssss” — this will cause inter-abdominal contraction.
  6. Continue this for seven seconds.
  7. Once finished keep the stomach in tight and repeat ten times.
  8. Do not relax the stomach until completely finished all ten repetitions.

Isometric Biceps Curl Warm up your biceps with a few light dumbbell or barbell curls. Nothing too taxing just enough to get them nice and warm, the blood flowing.

  1. Stand in the Smith Machine.
  2. Place an empty Bar at about shoulder height (you may have to vary this to ensure the maximum effect).
  3. Bring your hands up to the bar as though you have just reached the top of a barbell curl. Set it an inch below.
  4. Keep your back straight and your abs tense.
  5. Your biceps should be close to fully flexed at this stage. Relax — you haven’t put any weight on the bar, yet.
  6. Load the bar with a LOT of weight. Don’t underestimate your self.
  7. The object of the exercise is to raise the bar a little more than an inch. That’s it. Just an inch and then hold it there for seven seconds.
  8. If you can hold it longer than seven add more weight. Anything less, take some weight off.
  9. All you are doing to raise the bar is contracting your biceps as hard as you can. At no time should your elbows be directly beneath the bar.
  10. Really tense your biceps and forearms for all they are worth.
  11. You will feel the blood rush into the muscles — this causes the subsequent repair and growth of the muscle.
  12. Then rest. Take a week off training the biceps.


  1. Article on static strength training
  2. Charles Atlas and Isometric exercise
  3. Isometrics and steroid use
  4. Kenneth Baldwin at University of California
  5. NASA article on muscular hypertrophy and atrophy

External linksEdit