Isometrics Revisited

by Fitcoachion | Last Updated: September 18, 2020


An example of an isometric exercise

Isometrics is a strength training technique in which the muscle being loaded does not actually move, such as if you stand in a doorway and try to push the frame apart. Or you can try to flex your arm and resist with your other arm as shown in the picture. This is thought to be a useful approach for certain applications like physical therapy. It is also convenient because it is portable, you can do it while on travel with no equipment, and can even be done discretely in your office. But it is typically thought not to be a good substitute for “real strength training” (like weight lifting). But is that really true? This was revisited in a recent book by well-known strength coach Paul Wade: The Ultimate Isometrics Manual. I highly recommend this useful and interesting book. He reviews the history and science of isometric training, and concludes it is actually superior to conventional training for gaining strength, and at least as good for gaining muscle. This is a revolutionary statement because isometrics is much more time efficient than conventional exercise, and as I mentioned requires much less equipment (or even none).

It also causes much less soreness because there are no eccentric contractions: When you are doing a bicep curl with a dumbbell, the bicep muscle is contracting the whole time you are lifting and lowering the weight. When the weight is being raised, the muscle is shortening while under tension, a concentric contraction. When the weight is being lowered, the muscle is lengthening while under tension, an eccentric contraction. Eccentric contractions do microdamage to muscles and are thought to be the main contributor to delayed onset muscle soreness (DOMS). I knew about that. But here’s what I didn’t know. I thought the microdamage was what stimulated the body to strengthen the muscle. Many strength training books emphasize the importance of eccentric contractions, for example, emphasizing “negatives” (such as the lowering portion of the bicep curl).

But as coach Paul shows, the science supports that muscle strengthening and size increases are stimulated by a combination of how hard the muscle is contracting, and how much time. Strength trainers refer to this a time under tension.

The other main misunderstanding about isometrics, which I’ve read about in multiple places, is that it only trains the muscle at a specific joint angle. In the picture above, the guy’s right bicep is bent at about 90 degrees, so he is strengthening it at that angle, but what about if it is at 120 degrees (straighter arm) or 60 degrees (more flexed)? It was previously thought, and early scientific studies seemed to show, that it would only be trained at 90, the angle where the load was applied. More recent science has shown this to be false, the muscle becomes stronger in its whole range of motion.

To summarize:

  1. Isometrics are more effective than conventional weight training at strengthening muscles.
  2. Isometrics are at least as effective as conventional weight training at making muscles grow.
  3. Isometrics cause less muscle soreness so require less recovery than conventional weight training.
  4. Muscle soreness after you workout does not contribute to strength or muscle gains. “No pain, no gain” is true for the discomfort of the effort required during the workout, not the soreness afterwards.
  5. Isometrics actually improves resting heart rate and blood pressure with time, so it is “heart healthy”.

I’m intrigued enough by all of this that I’m going to give this a try for the next few weeks. My strength training will be exclusively isometric. I’ll be able to retest my strength from time to time using conventional weights. I’ll keep you posted how it goes. I was sold on the science behind the claims in the above list. I’ll go over a bit of the details later, for more I recommend checking out the science in the book. The book also has detailed suggestions on things like how hard the contraction should be, hold time, and reps. The bottom line should be go pretty much as hard as you can. For maximum strength gain, hold for about 10 secs, and repeat 5 times, for maximum muscle growth, hold for more than 20 seconds, and repeat 3 times. You only need to rest a few seconds between reps, so this is very time efficient. There are a some subtleties I’m glossing over, so I highly recommend checking out the details in the book.

The next interesting thing I got from the book was that there are three main ways, of increasing effectiveness, to do isometrics. In the first, you “clench” a muscle and its antagonist and have them fight each other. Considering the bicep again, if you clench both your bicep and your tricep (the antagonist to the bicep), they are fighting each other. This principle was used by Charles Atlas in his “dynamic tension” method. It is also used by bodybuilders for some of their competition poses.

The Classic Charles Atlas Ad with the kid getting sand kicked in his face

In the second method, you are pushing against external resistance, such as the biceps picture at the top, pressing against the hand of the other arm, or an external object, like the wall in this picture:

In the third, the muscle is loaded by an external load which it is resisting. In the figure the athlete is doing a goblet squat, with external load from both the dumbbell and the bands:

Imagine this were an extremely heavy load or extremely stiff band so she cannot straighten out, she’s straining against the load in the position shown. That’s the third type of isometrics. The most obvious way to do this is with bodyweight, like holding the plank, the half-squat position shown in the picture (the “horse stance” is a famous example of this from martial arts), or halfway down in the pushup position or from a pullup bar. The problem with these is they are not progressive in loading, but there are ways to get around that are covered in detail in the book. My approach is to add resistance bands.

Coach Wade reviewed something called the “load reflex”, which triggers the firing of muscle cells. He gives evidence that the third method of isometrics is superior at triggering this reflex. This means you can activate a higher percentage of the fibers in the muscles being trained, leading to better strength gains. Another important aspect is measurability, so you can keep track of progress. “Last week I was straining against 100 kilos but this week it’s 102”. This is a clear advantage of conventional weight training. He introduces an equivalent solution for isometrics with a device called the Isochain, which has a built in load cell with a digital readout. It’s a very clever and useful device, but costs about $500 US, and I’m the type that doesn’t like to spend that much when I’m first trying something out. I may be interested later if I really get into this. Coach Wade also covers alternatives using bodyweight and no equipment (what he calls “zero-tech”). There are some impressive examples given of strength feats with isometrics with bodyweight calisthenics that would make a gymnast proud, something the Kavaldo brothers are famous for. Al Kavaldo is featured in pictures in the boo. He’s the one horizontal in this picture, held by his brother Danny:

To try this out, I’ve come up with a setup that’s pretty effective using resistance bands, which I already use for a lot of my exercises instead of weights. I’m already used to the fact that resistance bands are less measurable than weights. With bands I can track my progress by noting “last week I was able to do chest presses with one arm against 4 of the black bands, but this week I was able to add one of the red bands”. You are still doing progressive strength training, but not as precisely. For me it’s enough. For isometrics, you do the same thing, using heavier bands that you can only push till the muscle is in the desired position. Here’s an example that combines bodyweight and bands:

In this “halfway down pushup”, I’m straining against my bodyweight and the resistance band to hold my position.Try this for 15 seconds and you can get a good shudder going in your muscles. This is an example of the 3rd type of isometrics. the best method. It is measurable in that I’ll be able to note I added more bands over time.

In the past, I’ve tried the most convenient form of isometrics, the “dynamic tension” described above. It may not be as effective, but I find I can get a pretty serious muscle contraction, even if it is not measurable. It sure is a lot more convenient, and I use it on travel. I do a combination chest press/row this way as well as a combination overhead press/lat pulldown, a combination curl/tricep extension, and an abdominal/back extension exercise. I’m a “perceived level of exertion guy” in general, so lack of measurability doesn’t bother me. On my bike, for example, I just know that I go “really hard” on my intervals. I don’t have anything fancy like a power meter or even a heart rate meter. But every couple of weeks or so I can doublecheck my progress with some kind of test, like how fast I can climb a certain hill. The same is true with isometrics, every so often I can test my improvement on a conventional weight challenge like how heavy a dumbbell I can do a tricep extension with.

The science

The next 2 figures are from The Ultimate Isometrics Manual, (part I, Isometric Exercise: The Science). The first shows the result of a study comparing strength gains and muscle growth with isometrics vs weight training with concentric contractions (raising) and eccentric contractions (lowering):

Muscle strength improvements are significantly better with isometrics, and muscle growth is about tied. As to why this is so, the science shows you can recruit a somewhat higher amount of the total fibers in a muscle with isometrics. But the real kicker is how the force in the muscle varies with time during a rep. The next figure is how the force varies for a bicep curl. The variation when using weights is expected from physics, there’s no load when the arms are straight, max load at about 90 degrees, and little again when the arms are fully flexed, due to how the leverage varies. But this can also be measured directly with electromyography (EMG): Isometrics is more effective because you can recruit more muscle fibers and the load remains high throughout the exercise instead of varying:

There’s a lot more science presented in the book. A vital piece of information for me is the isometrics has been shown to be heart-healthy. It has a reputation of causing high blood pressure. It’s true that blood pressure rises, during the exercise, that’s true of any vigorous exercise. But if you regularly practice it, your resting blood pressure goes down. So does your resting heart rate. These are both heart-healthy outcomes, important for an OG like me.

I think my favorite part of the book was the fascinating presentation of the history. Here’s one tidbit. I was a big fan of the great Vasily Alexeev, I loved watching him heave huge weights in the Olympics in his heyday:

His legendary coach, Professor Yuri Verkhoshansky, was a big-time proponent of isometrics, and it played a large role in Vasily’s training.