Walk into any gym and you will undoubtedly see two types of training performed isotonic exercises and isometric exercises. Isotonic training involves the classic lifts performed most frequently, with a concentric or “lifting” phase and an eccentric or “lowering” phase in each repetition. For simplicity, consider a standard biceps curl.
There is nothing wrong with isotonic training, and it has been tried, tested and true for facilitating gains in size and strength. But adding another type of exercise to the mix can be a missing link to unlocking more gains and overcoming plateaus you may have encountered in your quests for both insane strength and added size. This type of exercise is isometric exercises.
What are isometric exercises?
Simply put, while isotonic training involve shortening and lengthening a muscle to generate repetitions, isometric exercises involve no change in muscle length while applying forces against a resistance. For this to be possible, it would mean that the resistance would be too heavy to change the length of the muscle tissue — in other words, stationary. A simple example of an isometric contraction would be trying to squeeze a concrete wall with the intention of moving it (knowing, of course, that it won’t move).
Admittedly, at that time 10 years ago, I had no idea that isometrics could have a reliable impact on any goal. I had to review plenty of credible research and invest in coaching myself with an expert in muscle activation techniques using strictly isometrics as a training method to realize its benefits first hand. And the benefits are many.
Isometrics improve mobility
This sounds counterintuitive, but it is important to realize what mobility actually is. It’s power!
What makes mobility different from flexibility is the fact that a flexible person can experience lengthening of muscle tissue through stretching – and this is usually isolated to one or maybe two muscle groups at a time and relies on an anchor of some sort to passively move. (Think of standing tall, raising your leg on a straight-knee bench, and leaning forward over that leg for a hamstring stretch. This is an indication of your hamstring flexibility). Mobility relies on the contractile force of a group of muscles to affect the range of motion at a joint. It relies on actively pulling a joint through that range, rather than passively pushing it into that range (so again, think of the hamstring stretch, but this time imagine that the bench has been removed from under the leg. For to maintain the same joint angles would mean that the hips and quads at the front of the thigh must now contract to keep the leg up there level). In everyday life, good mobility far outweighs good flexibility in importance. And once again, accessing strength through a range of motion will make mobility better.
Isometric training can help with this tenfold by simply challenging the extreme areas of the lifters mobility. Here is an example. If a lifter has poor shoulder mobility in both extension and/or flexion, it is fairly simple to place something stationary at the limit of the lifter’s ability and apply isometric force to that object. Over time, once it becomes easy to reach that point and apply full force for a set amount of time, the object can be moved further away from the lifter to create a new challenge at what is now a new end range movement. In the case of the shoulder extension (see video below), this would simply mean raising the forearm a few inches higher.
How isometric exercises improve strength
Being isometric, as we discussed, the muscles do not change in length and in an ideal world, the skeleton does not change or change position while performing the exercise in question. This is invaluable for a lifter looking to avoid injury, as 99% of injuries occur when the body changes position under load.
This also allows you to do something that conventional isotonic training can’t: Increase your maximum effort at every phase and joint angle of the force curve of a movement.
The Isometric Deadlift
As you can see in this deadlift example, I’ve locked the bar in the bottom position of the deadlift to work on giving it everything I’ve got there. Then I could just as easily adjust the spikes to block me at the level just below the knee—a place where the moving bar would normally only pass through isotonic training—even if it’s a one-rep max effort. The presence of kinetic energy/force in the game meant that I could never really generate a true maximum force output through these areas.
This is humbling work and it won’t take more than 6 sets of 15 seconds to really drain your CNS.
Isometric bench press
You can repeat the same concept with bench presses and military presses or even squats.
Isometrics can cause size gains
Regular use of this training method can be of great help to someone looking to increase muscle mass. Think of it this way: Building muscle will be a product of recruiting high-threshold motor units, exhausting fast-twitch fibers through heavy efforts (or exhausting them to similar exhaustion through lighter efforts), and of course, supplementing it all with one goal—nutrition-based.
Using an isometric exercise to strengthen the CNS and recruit many of these high-threshold units for a given movement can make the transition to the isotonic version of that movement even more effective at a) creating time under tension and b) encouraging muscles to “overfire” due to simply being “tricked” into working against something immovable. A good example of this would be performing the isometric deadlift shown above, followed immediately by an 8RM deadlift.
Suffice to say, the possibilities for isometrics are endless. Incorporating them into your program is a surefire way to see gains while not putting your body at risk of working hard. It’s also important to remember that regardless of your skill level or athleticism, we work with energy systems. As long as the tool matches your strengths, you’re likely to feel the same sensations and die after the same amount of time whether you’re a beginner or a pro bodybuilder. That’s the beauty of it.
As a general guide, start with 15-20 seconds of isometrics for any of the above movements, aiming for maximum effort. After 4 weeks, move up to 20-30 second isometrics.
