Isometrics for Mass!

by Christian Thibaudeau

How to get bigger by not moving a muscle

A new way to use isometric training for size and strength.

Hold It Right There!

Can you get stronger by not moving a muscle? According to the scientific literature, yes, you sure can! Isometric or “static” training has been shown to stimulate strength gains in numerous studies. In the real world, I’ve been using it with success for years in my own training and with my athletes.

But can isometric training increase muscle mass as well as strength? There’s very little info out there on this topic. In fact, the literature seems to be telling us that isometrics can lead to strength gains without influencing muscle mass. So, understandably, this form of training never made it into the bodybuilding world. That’s too bad because it can be an effective tool for muscle gains!

Isometric Action Training: A New Dimension

An isometric muscle action refers to exerting muscle strength/muscle tension without producing an actual movement or a change in muscle length. Examples of isometric action training include:

  1. Holding a weight at a certain position in the range of motion. Example: Holding a hammer curl statically at about mid-range for a certain amount of time.
  2. Pushing or pulling against an immovable external resistance. Example: The iso-pull shown below.

Historically, it’s believed that we can produce more strength in a maximum isometric action than in a concentric contraction. While some studies do find a slight difference, Soviet literature concludes

“…there is not a statistically significant difference between the maximum strength, as measured in a static regime, and the maximum weight that can be lifted in the same movement.” (1)

While probably not as effective as yielding or overcoming training, isometric training can still be of significant benefit to most athletes.

Isometric Action: Muscle Activation Potentiator

One of the most important benefits of isometric action training is that it’s the contraction regimen that leads to the greatest activation level. “Activation” refers to the recruitment of the muscle’s motor-units.

A recent study comparing the level of muscle activation during isometric, concentric, and eccentric muscle actions found that a person can recruit over 5% more motor-units/muscle fibers during a maximal isometric muscle action than during either a maximal eccentric (lowering) or maximal concentric (lifting) action; that’s 95.2% for isometric compared to 88.3% for the eccentric and 89.7% for the concentric. (2)

These findings are in accordance with the body of literature that finds that a person can recruit almost all motor-units during a maximal isometric action. (3) What this tells us is that isometric training can improve our capacity to recruit motor units during a maximal contraction. In the long run, this improved neural drive could greatly increase one’s strength production potential!

In the past, isometric exercises have been described as a technique that should only be used by advanced lifters. I beg to differ. One of the biggest shortcomings of lower-class lifters is the incapacity to produce maximum intramuscular tension during a concentric contraction. Isometric exercise can thus be used to learn how to produce this high level of tension, as it requires less motor skills than the corresponding dynamic action. For this reason, I see isometric exercises as very beneficial for all classes of athletes.

A Stimulus for Strength Gains

Isometric action training (or IAT) can lead to significant strength gains, no question about that. In a recent experiment, strength gains of 14 to 40% were found over a ten-week period using isometric training.

However, it’s important to understand that the strength gains from an isometric regimen occur chiefly at the joint angles being worked, although there’s a positive transfer of 20 to 50% of the strength gained in a 20-degree range (working angle +/- 20 degrees). (5)

Some people might see this limitation as a negative aspect of isometric action training; however, some authors prefer to see this as a benefit because it allows you to exert a greater level of strength at a certain point in the motion, allowing the athlete to stimulate more strength gains at a point where he needs it the most (his sticking point).

So, the three benefits of isometric training can be summed up like this:

  1. Maximum intramuscular tension is attained for only a brief period in dynamic exercises (mostly due to the fact that the resistance has velocity and acceleration components), while in isometric exercises you can sustain that maximal tension for a longer period of time. For example, instead of maintaining maximum intramuscular tension for 0.25 to 0.5 seconds in the concentric portion of a dynamic movement, you can sustain it for around three to six seconds during an isometric exercise. Strength is greatly influenced by the total time under maximal tension. If you can add 10 to 20 seconds of maximal intramuscular tension per session, then you increase your potential for strength gains.
  2. Isometric exercises can help you improve strength at a precise point in the range of motion (ROM) of an exercise. This can prove to be very valuable to get past plateaus due to a chronic sticking point.
  3. Isometric exercise isn’t “energy expensive,” meaning that you don’t expend much energy by doing isometric training. So, you can get the benefits of IAT without interfering with the rest of your planned workout.

A Stimulus for Muscle Growth

While initial reports on isometric action training hypothesized that this type of training wouldn’t lead to significant muscle gains due to the absence of work, recent findings indeed conclude that an isometric training regimen can lead to gains in muscle size!

A study by Kanchisa et al. (2002) found an average muscle cross-sectional area (size) improvement of 12.4% for maximal isometric contraction training and of 5.3% for isometric training at 60% of maximum contraction after a training period of ten weeks. The authors attributed the gain in muscle size to metabolic demands and endocrine activities rather than mechanical stress and neuromuscular control.

It’s important to note that isometric action training still has limited applications for an athlete or bodybuilder. Yes, it can help increase strength and size, but without a concurrent dynamic (yielding and overcoming) program, the gains will be slow. In fact, some coaches note that gains from isometric exercises stop after six to eight weeks of use. (6) So while isometric training can be very helpful to work on a weak point or improve an athlete’s capacity to activate motor-units, it should only be used for short periods of time when progress has slowed down or when a rapid strength improvement is needed.

Isometric training can also be useful during periods of lowered training volumes. When you have to decrease your training load either due to fatigue symptoms or time constraints, isometric work can help prevent muscle and strength losses.

The “New” Isometric Training

Many studies don’t report a lot of muscle growth from isometric training. This is only because the old German model (Hettingter and Müller) of six-second actions was used in the initial experiments. This duration of effort, albeit adequate for strength gains, isn’t sufficient to cause hypertrophic changes in the muscles. In other words, it won’t make you big.

This form of training is called maximal intensity isometric training and it’s similar in effect to the maximal effort method (1-5 reps with 90-100% of your max), which leads to strength gains with little, if any, muscle size gains. However, using sets lasting 20 to 60 seconds will represent an important hypertrophy stimulus, similar in nature to the repetitive effort method (8-12 reps with 70-80% of your maximum).

Another important point is that most studies performed on isometric training were short term, often using an insufficient period to stimulate a significant increase in muscle mass but sufficient to cause neural adaptations leading to strength gains.

Lastly, the fact that isometric training is often associated with programs such as the “Charles Atlas Dynamic Tension” certainly didn’t help improve the image of isometrics among hardcore lifters!

Types of Isometric Training

Before I tell you how to use isometrics to gain muscle, it’s important that you understand the various types of isometric training. First we have two isometric regimens: overcoming isometrics and yielding isometrics. Understand that this doesn’t mean you’re combining a concentric (or eccentric) action along with the isometric action. The actual external outcome of the exercise is the same: there’s no movement at all. However, the intent during the exercise changes:

1. Overcoming Isometric

You’re pushing or pulling against an immovable resistance (e.g. pushing against the pins in a rack). Thus there’s no external movement but your intent is to move the resistance (even though that’s impossible).

2. Yielding Isometric

You’re holding a weight and your objective is to prevent it from going down. Once again there’s no external movement; however, your intent is no longer to move the load but to prevent its movement.

It’s important to understand that both techniques won’t have the same effect; for one thing, the neural patterns used in both cases will be different. Overcoming-isometrics may have a bigger impact on concentric strength and yielding-isometrics on eccentric strength and muscle mass.

The following figure shows what the various applications of isometric training are. The three types of applications are max duration isometrics (equivalent of the repetitive effort method), max intensity isometrics (equivalent of the maximum effort method), and ballistic isometrics (equivalent of the dynamic effort method). I’ll briefly summarize all three of those applications, but for bodybuilding purposes, only the max duration method is useful.

Max Duration Isometric (Repetitive Effort)

With max duration isometric exercises you’re pushing, pulling, or holding a submaximal load for as long as possible, going to muscle failure. For maximum effect you want to use sets ranging from 20 to 60 seconds in length. The effect of this type of training on muscle mass can be important as there’s a very significant growth stimulus placed on all of the muscle fibers.

With this method you can use both overcoming-isometrics and yielding-isometrics. However, I find yielding isometrics (holding a weight) to be much superior when it comes to max duration isometric training. In this case, a load of 50 to 80% for a duration of 20 to 60 seconds is best.

The max intensity isometric method is related to the concentric maximum effort method. You’ll try to maintain a maximum isometric action for 3-6 seconds. You can once again use either overcoming-isometrics or yielding-isometric, but in this case overcoming isometrics (pushing or pulling against pins or an immovable resistance) are best suited for that purpose and much safer.

This type of isometric training doesn’t have a significant impact on muscle mass, however, it can increase muscle density and myogenic tone (also called “tonus” or the firmness/hardness of your muscles). Its main effect is on maximum strength development. This occurs specifically at the joint angle being trained, so you’ll want to use multiple positions. There’s also some evidence that maximum isometric training can improve the capacity to recruit and synchronize motor-units (intramuscular coordination) even in dynamic movements.

Even though overcoming-isometrics are best for this method, you can still use yielding-isometrics. In this case you’d use a load of 100 to 110% of your maximum.

Ballistic Isometric (Dynamic Effort Method)

Be careful not to mix up iso-ballistic (or stato-ballistic) training with the ballistic isometric method. Iso-ballistic is a mixed regime method in which an explosive action is preceded by an isometric pause.

The ballistic isometric method refers to pushing against an immovable resistance for a very brief period of time (one or two seconds) while trying to reach peak force output as fast as possible (basically trying to go from zero force to max force in a couple of seconds). You can’t use the yielding-isometric method here as it doesn’t suit the nature of the exercise – the nature being to produce maximum isometric tension is as little time as possible.

This type of exercise is especially good to develop starting-strength and is very useful for any athlete involved in a sport where explosive starts from a static position are involved. But for bodybuilding purposes, it’s basically a waste of time.

Isometric Training for Bodybuilders

We’ve established that the only application of isometric training that bodybuilders should use is the maximum duration method, with a preference towards yielding-isometrics. That having been said, I personally use three variants of this type of training:

  1. Stand-alone max duration yielding isometrics.
  2. Max duration yielding isometrics as post-fatigue.
  3. Max duration yielding isometrics as pre-fatigue.

Let’s break those down:

1. Stand-alone max duration yielding isometrics

This is your basic isometric training method. You select one exercise per muscle group and then three positions per exercise. Select a load you’ll be able to hold for 20-60 seconds (I personally find 45 seconds to be the optimal duration). A load of 70-80% of your maximum will generally be a good starting point.

Perform anywhere from one to five “sets” per position, three being best in most cases:

  1. Hold statically at mid-range.
  2. Hold statically at full contraction.
  3. Hold statically a few inches after the starting position.

Perform all the “sets” for a given position before moving on to the next one. Keep the rest intervals short; 60 seconds is a good target. This type of training is especially effective when training with a partner: you can try to outlast one another and even make a betting game out of it! Just don’t make a drinking game out of it or things could get messy.

2. Max duration yielding isometrics as post-fatigue

With this variant you’re using yielding isometrics at the end of a regular set. After you’re finished with your prescribed number of reps, hold the mid-range position of the exercise for 20-60 seconds. The 60-second mark is a bit idealistic though; most will have a hard time reaching the 20-second mark!

The great thing about this method is that it’ll thoroughly exhaust all your muscle fibers, providing a phenomenal growth stimulus. However, it’s a very taxing method and you should never perform it for more than one exercise per muscle (if you use post-fatigue on all sets) or for more than one set per exercise (if you wish to use it with all of your exercises).

3. Max duration yielding isometrics as pre-fatigue

I’m not a big fan of using pre-fatigue methods as they’ll hamper strength gains. However, pre-fatigue can be a good tool to stimulate muscle gains. Only use it on isolation exercises or for minor muscle groups so that you can still train heavy on compound movements. This method is especially effective for biceps, triceps, traps and deltoids.

What you’re going to do is basically a superset: combine the stand-alone max duration yielding isometrics with regular training. So you succeed every “set” of max duration yielding isometrics with a concentric/eccentric exercise for the same muscle group.

For example:

Isometric Preacher Curl for Max Time

Use a load that’s challenging (i.e. a load you’d struggle to do for more than three perfect reps.) Hold the weight at a determined position for as long as you can or for at least 45-60 seconds. Use three different positions: elbows at 90 degrees, elbows fully flexed, and two inches from the bottom position. Perform two sets for each position.

Standing Barbell Curl

After each set of isometric preacher curls for max time, perform one set of 10 barbell curls. Don’t worry about tempo; just complete the reps with as much weight as you can.

You’re basically going to do six sets of 10 barbell curls.

Here’s what it’ll look like:

  • Isometric Preacher - Elbows 90 degrees for max time
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest
  • Isometric Preacher - Elbows 90 degrees for max time
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest
  • Isometric Preacher - Elbows fully flexed for max time
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest
  • Isometric Preacher - Elbows fully flexed for max time
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest
  • Isometric Preacher - Elbows almost fully extended
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest
  • Isometric Preacher - Elbows almost fully extended
    No rest
  • Barbell Curl x 10 reps
    45-60 seconds rest

This variation will produce rapid gains in muscle size and is especially useful in correcting specific weaknesses in your physique.


These three methods will allow you to reach a new level of muscularity in a short period of time. However, understand this doesn’t take the place of regular training. It should be seen as a supplementary training method only, but with proper application it’ll make your training more effective than ever!




  1. A.S. Medvedyev 1986.
  2. Babault et al. 2001.
  3. Allen et al. 1995, Allen et al. 1998, Belanger and McComas 1981, De Serres and Enoka 1998, Gandevia et al. 1998, Gandevia and McKenzie 1988, Merton 1954, Newham et al. 1991, Yue et al. 2000.
  4. Kanchisa et al. 2002.
  5. Roman 1986, Kurz 2001.
  6. Medvedyev 1986.