How to Use Yielding Isometrics & Eccentrics to Build Muscle Mass

Gerry DeFilippo
Written By: Gerry DeFilippo
October 24th, 2018
Updated: June 13th, 2020
Categories: Articles Training
18.2K Reads
How to Use Yielding Isometrics & Eccentrics to Build Muscle Mass
Learn how to use yielding isometrics and eccentrics to build lean muscle mass, strength, & to rehab from injuries. Check out how to use them in your workouts.

Over the past couple of months I have made great use of yielding isometrics and eccentrics in my programming for my athletes and clients.

In doing so, I have developed some great strategies on how to utilize these particular phases of a full range of motion as accessories in your programming that can help pack on some much desired muscle while building strength, and also serve as a quality way to rehabilitate nagging muscular and tendon related injuries!

I work closely with doctors of physical therapy and often; eccentric and isometric focused exercises are at the top of their lists of recommendations when it comes to helping a shared client along in their training/rehab.

Here is a detailed and easy to understand breakdown of yielding isometrics along with some practical ways to implement them in your programming.

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What Are Yielding Isometric & Eccentric Focused Exercises?

So already in this article I have mentioned that yielding isometrics and eccentrics are a great tool to use to build muscle mass, strength, and rehabilitate, but how exactly do they work and how do you go about performing them?

Let us look at each separately to understand. Since eccentrics are heavily involved in yielding isometrics we will start there.

Related: Eccentrics - Build Strength With Heavy Negatives


  • Essentially, an eccentric movement is any movement in which any muscle is active and lengthening while under a load.
  • It is very common to hear a trainer or lifter refer to eccentrics as a “negative,” when cuing tempo for a lift.
  • Examples:
    • The lowering of the bar to your chest during a bench press.
    • Descending into a squat.
    • The act of your arms extending during a curl.

Using an squat isometrically and eccentrically

Yielding Isometrics

  • A yielding isometric movement is one in which you hold a load and aim to resist eccentric forces.
  • As a result, eccentrics are also heavily involved in yielding isometrics.
  • Think of any of the eccentric examples listed above and imagine trying to stop yourself halfway through any of those movements and perform a timed hold. This is a yielding isometric!

Eccentrics & Yielding Isometrics for Building Muscle Mass

Now that you understand both eccentrics and yielding isometrics, this gives you a great clue as to what is occurring during both that helps build muscle mass.

Essentially, there are two types of hypertrophy. Both can be trained as follows:

Myofibrillar Hypertrophy

  • Myofibrillar hypertrophy involves the tearing of muscle fibers during eccentric and isometric exercises.
  • During myofibrillar hypertrophy contractile proteins (actin and myosin) become present and these proteins have been shown to heavily contribute to strength gains.

Sarcoplasmic Hypertrophy

  • Sarcoplasmic hypertrophy involves the increase in the presence of sarcoplasmic fluid around the muscles.
  • This fluid does not yield either proteins and thus does not contribute too much to gains in strength.
  • We can achieve sarcoplasmic hypertrophy via repetition alone.

In essence, sarcoplasmic hypertrophy is the effect many bodybuilders see from their training and is also the reason you can be massive and not have exact strength relative to your size. Meaning, the additional muscle mass you can gain that does not come from the tearing of fibers does not greatly contribute to strength and can leave a nice look, but not correlate to the strength you would expect.

Now, what sounds more appealing to an athlete or trainee looking to get strong while also building muscle? Functional muscle mass via myofibrillar hypertrophy correlates to strength gains, while muscle gains from sarcoplasmic fluid does not actually provide much of a performance benefit. Assuming that you want functional muscle mass, yielding isometrics and eccentric focused training are for you.

Rehabilitation Benefits of Eccentrics & Yielding Isometrics

When it comes to rehabilitation, eccentrics and yielding isometrics are great tools to build thick and dense muscle mass that can be lost via injury, surgery or inactivity.

For example, consider recovery from an ACL injury. After my affiliate physical therapists have complete rehabilitation with a client, I often will be instructed to further build muscle mass in their quadriceps that they lost due to the injury.

Instead of simply building muscle mass itself, placing this athlete or client through a course of eccentrics and isometrics can also help them gain back strength they have lost and will go along nicely with any strength specific training we are doing (I will touch more on this later).

In addition, slow and focuses movements brought on by eccentrics and yielding isometrics can be invaluable in terms of regaining muscular control. It is imperative to have full control over muscular contractions specific to main movement patterns that are used in training.

Using Eccentrics for Rehabilitation

How to Implement Eccentrics & Yielding Isometrics

Before I delve into specifics on how you can pair these with certain exercises in your workouts, here is one basic principal I like to use with eccentrics and yielding isometrics.

I stick to general principles of hypertrophy and aim to keep time under tension (total amount of time a muscle is contracted during a set) to 30-50 seconds.

Meaning, if you are performing an exercise with a strong emphasis on eccentrics you must add the time for the entire movement (concentric, isometric and eccentric), and keep the set roughly within the guidelines for hypertrophy. If you exceed this time you will be venturing into the range of muscular endurance.

Related: Pause Rep Workout Program for Serious Strength Gains

For yielding isometrics I generally will have an athlete or client perform a full hold as one set, but you can also implement pauses halfway through full repetitions if you chose. For sets involving one full hold you can begin with 30 seconds and gradually work your way up to 50 as you progress through your program.

My two favorite ways to implement yielding isometrics or eccentrics in my workouts thus far are as a second exercise in a superset that targets the same muscle groups as the first exercise or as the second exercise in a superset to accompany a concentric only movement.

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Targeting the Same Muscles in a Superset

  • Think of this as an accessory to your accessory work.
  • For example, if your unilateral movement of the day mainly targets the quadriceps you can implement an exercise such as the banded TKE immediately after your reverse lunges to further tear muscle fibers and build additional muscle mass/strength.

Accompanying a Concentric Only Movement

  • Another way you can utilize yielding isometrics or eccentrics are to pair them with concentric only exercises in which you are purely aiming to make strength gains.
  • As someone who programs in a conjugate manner (There is a “little bit of everything,” in each cycle and we do not focus on one specific attribute), this use is quite practical.
  • Consider a heavy prowler push. The sled does not push back on the athlete, and thus this movement is concentric in nature and mainly builds strength. Pairing a TKE isometric hold with these can still accomplish some hypertrophy goals and works as a nice compliment!

Now that you understand eccentrics and yielding isometrics you can utilize them and maximize the efficiency and effectiveness of your workouts.

Give them a try and notice immediate gains in muscle mass as well as strength!