Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
To include isolation work or not include isolation work; that is the question. As the answer will differ depending on your training level and age, we will primarily be answering this from a beginner’s viewpoint as that is where we find most of the nuance; that and beginners are the ones who usually wonder about this. In fact, if you don’t get this right, you may never even pass the beginner stages of lifting. And to be clear, often, you will find lifters who want to bash a style of training because they saw a Youtube video that said it was bad. That’s not what we’re doing here. We want to use scientific studies to explain why you may be wasting your time in the gym and even hindering your gains if you’re choosing the wrong exercises. In other words, we actually want to see you progress. That being said, let’s get into it.
Compound Exercises Vs Isolation Exercises
Before we even speak about if you should include isolation movements in your training, we need to be sure we are talking about the same thing. When we are choosing exercises to perform, there are two major categories; compound movements and isolation movements.
Compound movements are exercises which include the flexion and extension of 2 or more joints. This is why they’re also known as “multi-joint” exercises. Being so, they use a lot of muscle mass and usually let you move a lot of weight. Examples of compound movements are:
- Squats (hip, knee, ankle)
- Deadlift (hip, knee)
- Overhead Press (shoulder, elbow)
- Bench Press (shoulder, elbow)
You get the idea. Big movements - push ups, pull ups, bent over rows, etc.
Isolation movements are smaller exercises that only include flexion and extension at one joint. Again, they’re also sometimes known as “single-joint” exercises. Their primary purpose is to “isolate” a specific muscle group (as much as possible) in order to train it without the involvement of other muscle groups. You will generally see bodybuilders use isolation movements much more as they are trying to train each muscle on its own for optimal growth.
Common examples include:
- Bicep curls (elbow flexion)
- Tricep extensions (elbow extension)
- Lateral raises (shoulder abduction)
- Chest Flys (horizontal shoulder adduction)
- Reverse Flys (horizontal shoulder abduction)
- Leg extensions (knee extension)
So that’s the difference between compound and isolation exercises.
Should You Include Isolation Exercises In Your Workout Program?
The reason this is even a question is because when new trainees first go to the gym, they will almost always go straight for dumbbells and start doing curls. Then move to lateral raises. The reason being is that these movements are simple and easy to do. The form is also not as big of a factor (the form is always a factor, but there’s a huge difference between the form for bicep curls and the form for a deadlift), making them less intimidating to try. Unfortunately, if you have less than 1 year of progressive training under your belt, you are likely just wasting time - check out these strength standards to see where you stand.
Why Beginners Shouldn’t Use, Or Minimize Use, Of Isolation Lifts
We’ll get into the studies below, but first, we want to explain the reasoning of why beginners should minimize the use of isolation exercises. In a nutshell, a beginner lifter has way too much to improve to mess around with isolation exercise. A good way to think about this is to imagine you were painting the outside of your house (your body). When looking at your tools, you find that you have two choices, a big roller (compound movements) and a small brush (isolation movements). When you first begin painting, you’re going to use the roller as this is going to cover a lot more area in a faster amount of time. Once you get the majority of the work done, then you’ll grab the brush to hit any hard-to-get spots or areas that need a bit more detail. And this would be right as it's the most efficient method. Now picture someone coming and wanting to paint the whole house with a little brush. That’s what you’re effectively doing when you rely too heavily on isolation exercises when you’re just beginning.
Basically, when you first start, every muscle group on your body has plenty of room to grow and needs training. However, a muscle can only grow so fast after one workout. This means that if you apply any sort of stimulus to your muscle as a beginner, it’s going to grow. In other words, there’s no need to isolate a muscle because it’s already getting sufficient stimulation from the big compound exercises. Further, adding more stimulus won’t result in any further growth simply due to the growing rate of a muscle (see below to see studies that have proven this).
When more advanced lifters use isolation exercises, they have reached a point in their training where isolated muscle groups have reached a point where they need to be isolated for continual progress. One reason for this is the concept of “the weakest link”. Basically, when we use compound exercises, we are limited in the amount we can lift which is determined by the weakest muscle. For example, let’s say you exercise using muscles A, B, and C. However, muscle C has not responded as well as the other muscle groups during your training, so it has lagged behind. Therefore, muscle C fatigues before muscles A and B can reach a stimulus sufficient to grow when you perform the exercise. However, as mentioned above, this isn’t a concern for beginners simply due to the potential growth in all of their muscles.
Perhaps even more important is that while isolation movements can produce muscle hypertrophy (muscle growth), their ability to increase muscle strength is mute. One of the reasons for this is due to neurological adaptations just don’t occur to the same extent. In order to increase your strength, your muscles must learn to work together. This is because movements rely on the proper firing of muscles to produce the greatest amounts of force. When you perform isolation work, you are only using one muscle, meaning it’s not learning how to work with other muscles. Further, the heavy loads required for strength gains just can’t be applied to isolation movements, at least not safely.
Studies Explained
After reading the explanation, it kind of makes sense; still, let’s look at some studies that show this to be reality. And there are actually quite a few.
1. Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects (2013)
This first study had an extremely simple methodology. The researchers divided a group of untrained men into two groups, with one group performing a strength and conditioning routine using only multi-joint exercises. The other group completed the exact same program as the first with the multi-joint exercise but then added single-joint exercises. In other words, the second group who added the single-joint exercises actually did more volume, making you think they would have more significant gains.
However, the results showed while both increased muscle mass and strength, neither group outperformed the other. To be clear, the group who did the extra single-joint exercise saw no additional gains in strength or size. This is even more amazing because the multi-joint group only performed 2 exercises (bench press and lat pulldown). You would think that with this little volume, the added single-joint exercises (elbow extension and elbow flexion) would elicit more gains. In reality, it seems they just wasted their time.
2. The effects of adding single-joint exercises to a multi-joint exercise resistance training program on upper body muscle strength and size in trained men (2015)
Basically, this study is the same thing as the one above. One group performed a resistance training protocol only using multi-joint exercises. Another group did the same program but added single-joint exercises. Again, the same results. Neither group outperformed the other except the single-joint group spent more time in the gym. However, this study is interesting because it was done with trained men; each participant had at least 2 years of training. And still, single-joint exercise offered no additional benefit!
3. Does the addition of single-joint exercises to a resistance training program improve changes in performance and anthropometric measures in untrained men? (2018)
Another study showing the addition of single-joint exercises offered no benefits to a protocol using only multi-joint exercises.
4. Resistance Training with Single vs Multi-joint Exercises at Equal Total Load Volume: Effects on Body Composition, Cardiorespiratory Fitness, and Muscle Strength (2017)
This study changed things up a bit as they had two groups follow different resistance training protocols. One group only performed multi-joint exercises, and the other group only performed single-joint exercises. The one controlled variable was volume in that each group performed the same amount of volume, which was calculated by Sets x Reps x Load.
While both groups had similar increases in muscle mass, the multi-joint group saw greater improvements in their VO2max and muscle strength. So, while a die-hard fan of arm curls might say you can grow just as much muscle with a single-joint exercise, the multi-joint group improved their cardiorespiratory system to a greater extent and had greater neurological adaptations which we spoke about above. Also, we need to discuss the equated volume. As the multi-joint exercises used 6-8 reps for their training, the single-joint group had to use anywhere from 12-18 reps in order to equate for volume. This doesn’t reflect reality as gym-goers generally stick around 8-12 reps for hypertrophy. In other words, the single-joint group was doing more work than what’s usually seen, which theoretically should have been an advantage.
There are more studies, but you get the point. It seems that isolation exercises don’t really seem to offer much benefit assuming you’re following a structured training plan and employing progressive overload.
So Why Are All The Professional Bodybuilders Doing Curls?
There are several things to consider with this question. The first is that professional bodybuilders have been training for years and have reached a point in their careers where they need to perform isolation movements in order to create a sufficient stimulus for growth. Remember that we are saying “Beginners should not be doing isolation exercises”, not “nobody should do isolation exercises”. In fact, this is one of the main culprits of bad advice. Just because one method is right for this person, it does not mean it’s suitable for you. Every single trainee has a set of different variables that will.
Secondly, not every bodybuilder should be a trainer. That’s just the reality. Often, they will suggest you train the way they do, which is horrible advice. In fact, many of the “hardcore” bodybuilding routines that include doing a ton of isolation and special sets are definitely not suitable for your average trainee.
Can I Ever Knock Out Some Bicep Curls?
Absolutely! First and foremost, we love getting a crazy pump; even if we know damn well, it’s transient and will likely have a minimal effect, if any, on our arms. Further, we need to clarify that even though the single-joint exercises didn’t offer any benefit, they also didn’t cause any negative side effects. We simply propose the idea that the bulk of your training should be done using compound exercises and save one or two isolation movements for the very end if you have time. In other words, single-joint exercises should never take the place of a multi-joint exercise.
However, if you’re done with your training and want to knock out some dumbbell bicep curls, we say, “Go for it!”
Exceptions To Minimizing Isolation Work
Very few rules should be taken as a blanket statement, including this one. There are some instances where isolation work is definitely acceptable:
- You are recovering from an injury.
- You have an obvious deficit.
- You are involved in an activity that is known for certain injuries i.e. conditioning the bicep for Strongman competition (Strongman are prone to bicep tears due to the odd lifting).
When Can I Start Adding Isolation Movements?
As we said, you never have to totally give up on bicep curls. That being said, when we look at the one study above, isolation movements still gave no benefits to those working out for two years! While that’s one study, it seems that for most guys in the gym, isolation work should never be the main focus of your workouts UNLESS you are advanced or as “enhanced”. Again, it’s very hard to give a solid answer as the studies aren’t that specific but the majority of guys we see in the gym should just learn to master the foundational movements..
Last Notes on Isolation Exercises:
Remember that we are talking about isolation movements here, so you can still do hypertrophy movements. Another note to consider, when looking at the studies, many of them used elbow extension (triceps extension) and elbow flexion (biceps flexion). The only one that used isolation movements for the chest and back was the multi-joint program vs single-joint program study, which resulted in similar growth. However, we like the idea of adding isolation work for the back (rear flys, swimmers) and chest (chest flys, chest pullovers) more than we do for the arms ( curls, triceps extensions).
So as an example, when writing a program for the back, it may contain 6-7 exercises:
- 3-4 Compound Back Exercises
- 2 Back Isolation
- 1 Bicep Isolation (We will always love the pump!)
Concentrate On Your Foundation!!!
The main point you need to take away is to always focus on your foundational movements.. If your overhead press sucks, doing lateral raises is a waste of time. Get your press strong first, and then worry about building caps. You will never be wronged if you perform your big foundational movements with progressive overload; we can promise you that. Concentrate on those exercises, and once you’re finished, then you can get your pump on!!!
Here are 3 of our favorite workout plans to follow for strength & hypertrophy:
Prepare to maximize your gains with our exclusive 12-week hypertrophy training program. Choose between a 4 or 5 day training split and gain 2-12 pounds of muscle over 90 days...
Garett Reid
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