I’ve long used isometric exercises as a supplementary fitness modality for everything from minimalist exercise routines while traveling to build strength and muscle when my joints are unable to move through full range of motion to giving me extra moves to do during my daily sauna routine. Unfortunately, isometrics are a widely overlooked (despite their proven efficacy and use by professional athletes, weekend warriors, and aging seniors alike) exercise modality and often surrounded in myth.
The most common myths about isometrics are: 1) They don't build muscle, 2) They're only useful for specific sports where the muscle doesn’t change length frequently (like skiing, climbing, or grappling sports), and 3) They create excessive strain on the cardiovascular system.
If you’re an avid reader of mine, you already know that there is plenty of science to debunk the myths around isometrics—which I've recommended as a way to get fit in your car, supplement your training to build athleticism (via isometric yoga routines), increase growth hormone levels and muscle hypertrophy by doing single set exhaustive isometrics to failure, and more.
Not to mention, they're a great way to hone in on and work specific muscles with maximum precision. Think about it… If you're running a marathon, shoveling snow, or lifting a piece of furniture, engaging the wrong muscles, even for a moment, can lead to poor technique, less-than-ideal force, and an increased risk of injury. Isometric training allows your body to learn how to engage the correct muscles through positions that emphasize maximum activation of the specific muscle or muscle group you're focusing on. You simply have less distraction and more time under tension for the particular position you’re trying to learn or perfect.
In today's article, you'll learn all about isometric exercises and other ways you can put tension on your muscles, how isometric exercises can help you attain specific fitness and wellness goals, and how to biohack your way through fitness plateaus by tracking, measuring, and adjusting your isometric training regimen. A recently published book that I just finished may also pique your interest because it takes an even deeper dive into the science and efficacy of isometric training. It is called The Ultimate Isometrics Manual: Building Maximum Strength and Conditioning with Static Training and you can get it here.
3 Ways You Can Put Tension On A Muscle
The average gym-goer knows that exercise, at its core, is about making your muscles do work. Repeatedly put tension on a muscle, and it responds to the stress by getting stronger over time.
But what most people don’t know is that there are 3 different variables you can play with to change the adaptation response in your muscles.
These variables correspond to the 3 modalities of exercise, which are as follows:
1. Isotonic Exercise
Meaning “same tension,” isotonic exercise is the one most people are familiar with. You keep the load on your muscles constant, then move it at non-constant speed, while your muscles lengthen (eccentric) and shorten (concentric) to do the work. This is what’s happening when you swing a kettlebell, run on a treadmill, or perform a deadlift.
Whether the contraction is concentric or eccentric, the underlying action is the same: The muscle contracts and moves the joints it is attached to. Since it builds power throughout the range of motion, isotonic exercise is a foundational type of exercise. It builds strength, increases muscle mass and bone density, and ramps up your metabolism so you can burn more fat.
The downside? Joint movement leads to wear and tear, and as you produce more force, the potential for injury increases—so it’s crucial to have rest days and incorporate active recovery modalities such as foam rolling and others I go over in this article, especially as you get older and put more miles on your joints. As Joel Greene and I discuss on “How To Reshape Fat Cells, Enhance Repair During Sleep, Target Your “Circaseptan Rhythms,” Build Young Muscle & Get Rid Of Old Muscle.“, deep tissue work/foam rolling is key to increasing circulation and maintaining “young muscle.”
2. Isokinetic Exercise
Meaning “same speed,” isokinetic exercise is the least common modality. The goal with isokinetic exercise is to keep the speed of motion constant, but vary the tension to match the force applied during the exercise. This varying tension allows your muscle to be loaded to its maximum capability throughout every point in its range of motion.
Because of the precision involved, most isokinetic exercises are done on highly specialized machines used for rehabilitating injuries and increasing mobility, and thus tend to carry a lower risk of injury than isotonic exercises. (While the joint is still receiving wear and tear, the potential for improper technique to cause injury is greatly minimized when you control for speed.)
A stationary bike is the perfect machine to illustrate how isokinetic exercise works. Let's say you're pedaling at 100 revolutions per minute (RPM) at resistance level 2. Staying at 100 RPM while suddenly increasing the resistance to level 5 would result in the need for you to pedal harder in order to maintain your pace. If you are able to maintain 100 RPM at this increased resistance, you would be engaging in isokinetic exercise.
3. Isometric Exercise
Isometric means “same length” and is a form of exercise that causes tension in a muscle, or muscle group, but does not result in the muscle changing length or movement of the affected joint. In other words, an isometric exercise is one that involves muscle engagement without movement.
Studies have shown that isometric exercises allow you to recruit more muscle during training and can build muscle just as effectively as other muscle-building exercises if you do them at a high intensity and hit the same muscle from different angles. Isometrics also present fewer risks than the other two modalities since the joint never moves once you’ve engaged in an isometric exercise.
Wall sits or planks are good examples of isometric exercises, but you can actually turn almost any position into an isometric hold by applying tension against an immovable object and tricking your mind into thinking it’s moveable. If you want to try an isometric exercise, stand next to a wall in your home and chest-press it as hard as you can. Every bit of force that you apply will be matched by the wall, and you’ll exert a great amount of force without moving at all.
Why You Shouldn’t Ignore Isometrics
Remember how I explained exercise as “putting tension on a muscle?” It turns out that there’s a definable relationship between the amount of tension you put on a muscle and the results you get.
The most important variable in strength training isn’t load, or reps (although those do play a part)—it’s how much time under tension you can cram into a workout.
As you increase time under tension, especially peak tension, mitochondrial and sarcoplasmic protein synthesis are elevated by as much as by 114% and 77%, respectively. Increased mitochondrial synthesis allows for a more efficient conversion of energy into ATP, meaning more energy is available to your muscles. Sarcoplasmic proteins are found within the sarcoplasm (cytoplasm of the muscle cell) and are responsible for metabolism within the cell. While sarcoplasmic gains are great for seeing a metabolic response to training, maintaining blood flow, and allowing you to look buff in a swimsuit, they're not necessarily going to result in an increase of strength and are the reason you sometimes see bodybuilders being out-lifted by guys half their size.
During isotonic and isokinetic exercises, your muscle only hits peak tension during a very small portion of the movement (about 0.33 seconds). Compare that to the same movement done with isometrics, where you can hold maximal tension for up to 8 seconds. One isometric exercise, done at full power, offers a 24X increase in your time under tension!
Isometric exercises not only help you maximize time under tension, but they also recruit more muscle fibers than the other two types of contractions. Done properly, an isometric contraction activates up to 95% of the fibers in a muscle, compared to about 88% for isotonic modalities. That 7% makes a huge difference when you’re trying to break through plateaus, and since you get so much more time under tension in a small window of time, it’s easy to supplement your current regimen with isometrics.
How Isometrics Can Help Your Fitness Goals
Most people train for any number of the following reasons: muscle growth, athletic performance (and subsequent fat loss), or general cardiovascular health.
Isometrics can help you achieve each of these goals.
If you’re looking to gain muscle mass, remember that your goal is to induce myofibrillar hypertrophy (muscle fiber growth). More time under tension leads to more tearing of muscle fibers, which leads to more growth as your body repairs those small tears. It’s important to lift heavy loads with isotonic movements, but you can supplement with isometric training. After your usual isotonic lifts, you can maximize time under tension by incorporating isometric exercises such as negative pull-ups or lowering the bar as slowly as possible after a bench press or deadlift. In essence, you're forcing your muscles to fail, which is where myofibrils begin to tear. If you want to improve performance and work your fast-twitch muscle fibers, you don’t need to move faster, you need to load them with more force, and isometrics can help with that.
Henneman’s size principle dictates that muscle fibers are recruited according to force requirements. Since muscles move slower when they produce more force, isometrics recruit the most fast-twitch muscle fibers during training, because the muscle’s velocity is zero. Paradoxically, isometrics make you fast, and this goes beyond training your fast-twitch muscle fibers. By strengthening your muscles with isometrics, you improve their ability to handle torque and flexion. With proper isometric training, your tendons can stretch and recoil more, providing explosive power.
Isometric exercises also improve performance beyond the specific angle you're training at, with performance increases up to 15 degrees away from your training angle. This makes isometrics quite practical for strengthening your hips or knees through their full range of motion, so long as you map out the full range of motion when you’re putting a regimen together.
Regarding cardiovascular health, isometric exercises have been shown to be more effective at improving cardiovascular fitness than aerobic and resistance training. The myth I mentioned in the intro that isometrics “create excessive strain on the cardiovascular system” is simply a misunderstanding of the isometric effect. As you perform an isometric exercise, the tension in your muscle fibers translates to stress on your blood vessels (they’re basically squeezed by your muscles). This was originally misunderstood as a danger, but we now know that stress forces your body to adapt. When you place a moderate amount of stress on your circulatory system, it responds by building more blood vessels, strengthening your heart, and improving elasticity in your blood vessels.
To train for general cardiovascular health, just do some isometric training every day. If you’re concerned about your heart health and want to exercise maximum caution, then split the training up into a few 5-minute sessions throughout the day. If you’re at risk for cardiac events, of course check with your doctor first. It's important to note that training for general cardiovascular health is far different from training your cardiovascular system for an endurance event such as a triathlon or marathon. For more on endurance training, check out Part 1 and Part 2 of my article series, “The Two Best Ways To Build Endurance As Fast As Possible (Without Destroying Your Body).”
One added benefit of isometrics is their uncanny ability to point out your weak points. For example, when you’re holding a pike, the weakest part of your body begins to scream a lot sooner than the others. So you can focus on those areas to see quick performance gains.
Why Aren't Isometrics More Widely Used?
So if isometric exercises are so great for strength, performance, and cardiovascular health, then why isn’t absolutely everyone using them?
There are a few reasons. For starters, most forms of training have simple yardsticks to mark progress (add more weight to the bar, reduce your lap time, hit the ball further), but these types of indicators are not so readily apparent with isometrics.
Sure, you can hold a plank for longer, but if you’re pressing against a wall, how can you tell if you’re doing it with more force over time? One way is to measure your output with a dynamometer, but these can be limited in their application to your entire body. A simpler, but more onerous test, is to benchmark yourself with weight-room analogues of the exercises you’re doing. That chest press against the wall can be measured with a bench press, for example. Set aside one workout a month to check your strength against your benchmarks.
As I mentioned earlier, isometrics do improve strength in an average of a 15-degree radius from the actual muscle you're focusing on, but it’s actually a little more complex than that. It can actually be as much as 75 degrees in positions where the muscle has lengthened and decreases as the muscle gets shorter. Since you’ll want to train the full range of motion, it’s important to develop a plan where you attack your muscles at multiple angles, especially at angles where the muscle is lengthened. Problem is, how the heck is the average person supposed to figure out these angles and be sure they're covering their full range of motion?
Then, there is the mental barrier. If you actually got up and tried chest-pressing your wall while reading this article, you might have noticed something. In the back of your mind, you knew the wall wouldn’t move, so you held back a little. This can partially be attributed to neurological inhibition, which is when your body artificially limits the amount of force a muscle generates. This has some real benefits, like preventing tetanic contraction, but it’s a reflex that applies whether or not there’s any real risk. This inhibition can be gradually and safely “trained away,” but you may find that you have your own mental barrier, unrelated to any reflex, around generating force in an isometric exercise.
So what do you do if you're looking to get started with isometric training? I recently discovered a simple tool that addresses everything I just mentioned and takes all of the guesswork out of isometrics.
How I'm Incorporating Isometric Training Into My Workouts
In the past, I’ve talked about a few isometric tools and protocols previously, most notably the PeakFitPro, which will give you one heckuva grueling workout (the IsoChain described in this book is another good example)…
…but in terms of portability, accessibility, and versatility, nothing beats this tiny little device I've been using lately that I can literally fit into my pocket (seriously, it's about the size of a hockey puck) called the Activ5.
Yes, you can do isometrics without a device like Activ5, but you’ll have to put in your own work to address the problems of measurement, range of motion, and muscle inhibition. This little device eliminates the need for that.
Just pair it with your phone, and the app guides you through an isometric workout of your choice, all while measuring, assessing, and tracking strength in every part of your body. You can put the device between your hands, under your feet, press it against your shoulder, hips, thighs, and other muscles, and even use it between the small of your back and the floor. This thing tracks the force you’re generating in any given position, then guides you through the optimal load to increase strength, quickly.
So how does Activ5 address isometric exercise hurdles like measurement, range of motion, and neurological inhibition?
Activ5 measures the strength of your individual muscles with much more precision than the incremental “one-rep max” approach, or others like it. By engaging in quick isometric exercises focused on specific areas of your body, you can understand exactly how you are, or are not, progressing in building strength. Then you can isolate the areas that need work and see your progress grow over time with granular, highly accurate data.
As far as training your full range of motion, Activ5 helps you eliminate imbalances with pre-programmed workouts that attack the same joint from a variety of angles—building strength throughout the full range of motion. It also measures the strength of your individual muscles and how they change over time, helping you isolate asymmetrical muscles and offering workouts to improve symmetry.
Activ5 uses gamification to make your workout fun and enable you to break past the mental barrier of isometrics. The Activ5 app will guide you through an exercise with a simple display (a dot and a line). The line rises and falls as the whole screen scrolls to the right, and the dot will rise and fall based on how hard you press the device. Your goal is to keep the dot on the line, and this simple gamification does wonders for forcing you past mental limits and getting you to squeeze out a little more power.
The app offers a wide variety of workouts that are anywhere from 5 minutes long to nearly an hour. One of my favorite things about the device is, as someone who is constantly on the go, that I can do these workouts anywhere—in the airport, hotel room, backstage before a speaking gig, etc. Stuck on a plane for 5 hours? Just select the “sitting filter,” and it'll show you only exercises that can be done while seated.
If you're a fan of Pomodoro breaks for doing deep, high-quality work in short, focused sessions, Activ5 is perfect for filling those breaks. The effects of physical activity on your focus and mental clarity are undeniable, which is why light exercise is highly recommended as a way to break up your workday.
Activ5 also isn't just for building muscle, boosting athletic performance, or improving cardiovascular health, it is also useful for injury prevention in a number of different ways. Activating, or “turning on” certain muscles through isometric exercise is a highly effective warm-up or supplemental technique when engaging in rigorous exercise or strength-training and helps reduce the risk of injury. Perhaps more significantly, the trove of data the Activ5 app offers gives you a detailed and valuable view of the progress and effectiveness of your training efforts, helping you avoid overtaxing specific muscles and allowing you to focus on building strength in key areas that will help improve overall fitness and avoid unnecessary injuries.
Activ5 is also used by physical therapists to help their patients recover strength and agility in specific muscle groups. Since they don’t require joint movement, isometric exercises can help reduce pain in injured muscles while building muscle mass and improving endurance. I’ve also found that Activ5 is an ideal tool to assess, measure, and track progress while recovering from injury. So overall, when it comes to isometric exercise and the gamification and education of isometric exercises, it's a handy little device. Whether you’re just getting started in isometric training, a professional athlete (the device is used by the Pittsburgh Steelers and several Olympic-level athletes), or a grandparent who wants to be able to pick up your grandbaby, it is a promising way to build, measure, and track your strength. To get your own Activ5, just click here and use code GREENFIELD15 to save 15%.
Isometric exercises have been proven to assist in building muscle via increased time under tension and muscle fiber tearing, improve athletic performance by activating fast-twitch muscle fibers, and strengthen the cardiovascular system by causing your body to adapt and rebuild.
There's no disputing it, no matter what your fitness goals are right now, you stand to benefit by adding isometrics to your daily routine.
It can be as simple as holding a lockout until failure or beginning your day with some planks, but the more you put into this training modality, the more you can get out of it.
Be sure to check out my podcast “The World’s Fastest Workout: The 10 Minute Exercise Biohack Scientifically Proven To Produce 50%-300% More Strength & Muscle In Just 5% Of The Time.” for more on isometrics and also the book The Ultimate Isometrics Manual: Building Maximum Strength and Conditioning with Static Training. As mentioned above, Activ5 device is a great option as well and gets bonus points for its functionality, portability, and affordability.
If you have any questions, thoughts, or comments about isometric training, or want to share ways that you’ve incorporated it into your training, drop them in the comments section below.