What are isolation exercises and why are they needed?

Author: Timko Ilya - master of the whole project and fitness trainer.
2018-08-13

I've already written an article about basic exercises, and now it's time for isolating exercises. On one hand, all exercises that are not basic are isolating. So this article might not have been necessary. But it's a bit more complicated than that. So let's start with the definition.

What are Isolating Exercises?

Isolating exercises are those exercises where the main work (at least 80% of the load) is performed by only one muscle or muscle group.

For example, when you do:

And train the biceps, a little bit of the forearm and the anterior deltoids work too, but 80% – 90% of the total load (with proper technique) is still taken only by the biceps. That's one muscle. Now, an example concerning a muscle group. Let’s take the exercise:

The leg curl works three muscles: the biceps femoris, semitendinosus, and semimembranosus. This is also an isolating exercise. The thing is, if several muscles are closely located to each other and perform the same function, we usually refer to them as a muscle group rather than a specific muscle. I hope that's clear.

Now, regarding the 80% - 90% load. Why not 100%? The fact is, there are no exercises and conditions under which 100% of the load would fall only on one muscle. Simply because our muscles do not exist in isolation; they are part of one body. Well, the minimum of 80% is just how I decided to define it.

The next reasonable question: How do I know that only one muscle/muscle group is working? That's a good question. It's not always obvious, especially for beginners. To clarify, remember one thing:

Almost all exercises that involve movement in only one joint (paired joints count as one) load only one muscle/muscle group and are, therefore, isolating.

This is much easier to understand. For example, the same bicep curls with a barbell. The movement occurs only at the elbows—this means it's an isolating exercise. However, if, for example, you start doing chin-ups with an overhand grip, changes will also occur in the elbows and shoulders, and this is already a basic exercise.

But as mentioned earlier, not all exercises fit this definition. Some involve changes at only one joint while working several muscle groups. There are only a few such exceptions. Here they are:

In hyperextensions and reverse hyperextensions, only the hip joints are engaged, but the glutes, back extensors, and hamstrings work as well. In pullovers and straight-arm pulls, the lats and chest are involved, although only the shoulder joint changes (with the proper technique). These exercises can be termed under-basic or re-isolating.

Why Are Isolating Exercises Needed?

Such exercises are needed for the following reasons:

1. To load the desired muscle/muscle group with minimal energy expenditure. It's simple: if only one joint and one muscle group are working, the energy expenditure will be low.

2. To "finish off" the needed muscles after basic exercises. When you have no strength left after the basics, but you don’t feel that the necessary muscles have adequately fatigued.

3. To fatigue specific muscles before basic exercises. This is known as the pre-exhaustion method. It's when a person intentionally fatigues the necessary muscles to feel them better during basic exercises.

4. To reduce the load on the joints.

The last goal is quite controversial. Consider this: if only one joint works, then all the load falls solely on it. This is well felt in all French presses. Be it:

With relatively light weights, the elbows will bear a very large load. That's why most isolating exercises are performed with weights that allow a MINIMUM of 10 repetitions.

However, quite often, "isolation" does indeed put less strain on the joints than the basics. For example:

They load the knees quite lightly. And

they don't put much stress on the shoulder joints either. I think you can provide further examples yourself.

Conclusions

1. "Isolation" is just as important as basic exercises. Without it, workouts will be less varied and more boring. Additionally, mental energy is expended on the basics. Agree that preparing mentally is much stronger when it comes to

than for

Therefore, by focusing solely on basics, you quickly become exhausted both physically and mentally.

2. Personally, I use both basics and isolation in the workouts I write for you, in a ratio of about 60/40 in favor of isolation for beginners, and 40/60 for experienced athletes.

3. There are muscle groups for which isolating exercises do not exist due to their anatomical positioning. All these muscles are located on the back:

• Back extensors (lower back)
• Latissimus dorsi
• Rear deltoid

The spinal extensors cannot operate in isolation from the glutes. The latissimus dorsi always involves pull and tug movements. The biceps and rear deltoid also work here. An exception is pullovers, where the chest is involved. The rear deltoid always works alongside the trapezius and the muscle group surrounding the scapula.

4. Now I think you understand that it’s not that simple, and you can’t just say that everything that isn’t basic is isolation. There are different kinds of isolation. Good luck!