Review of Scientific Studies with Questionable Conclusions (Part One)
Doug Brignole / September 2022
A study was recently done which attempted to compare the resultant muscle growth of two different triceps exercises. The two exercises that were compared were the “Overhead Cable Triceps Extension”…and the standard “Cable Triceps Pushdown”.
The 21 participants performed one of the two triceps exercises with their left arm, and the other triceps exercise with their right arm — for a 12 week period of time. Then the triceps growth of each arm was measured. The conclusion of the researchers was:
“Triceps brachii hypertrophy (growth) is substantially greater [using overhead elbow extension versus neutral arm elbow extension]”
This study — and the conclusion of the researchers — was reported in “PubMed.gov” (National Library of Medicine), among other journals.
This conclusion was then widely reported in a variety of fitness journals, touted by numerous “evidence-based” personal trainers, and announced as fact by professors of exercise physiology…throughout the world.
“Insider.com” published a report on this study, with the following headline:
“Stop doing triceps pushdowns if you want bigger arms…overhead extensions may lead to significantly more muscle growth, according to a study published July 12, 2022 in the European Journal of Sport Science”.
However, I believe there is a flaw in this conclusion, and it stems from the assumption that the only difference between the two exercises was the position of the arm, relative to the shoulder joint (i.e., one using an overhead arms-up position, and the other using arms down alongside the torso position).
That was not the only difference between the two exercises. It was not even the primary difference, although it might appear that way to most people.
The researchers attributed the “significantly better triceps hypertrophy” exclusively to the “arms up” / overhead position. However, the “neutral arm” exercise they selected for the study (i.e., “Cable Pushdowns”) typically has a very compromised resistance curve, while the “overhead” exercise they selected typically has a much better resistance curve, during which the direction of the resistance is more perpendicular to the forearm, at the beginning of the range of motion.
The resistance curve of each exercise seems to not have been addressed.
In order to accurately assess the value of a “resistance exercise”, consideration of the mechanics that are occurring outside the body (i.e., the physics of the exercise itself) is essential. It’s not just the anatomical position that should be considered. The resistance curve of the both exercises being compared must be exactly the same, in order to eliminate all possible confounding variables.
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To see how this oversight occurred, let’s begin by reviewing the triceps anatomy.
The triceps muscle is compromised of 3 parts. These are known as the “Long Head” (Longus), and the “Lateral Head”, and the “Medial Head” (Medius) — shown below.
The “Long Head” originates on the outer edge of the shoulder blade (the “scapula”…indicate by the black arrow). The other two parts — the “Lateral Head” and the “Medial Head” — originate on the upper arm bone (the “humerus”)…indicated by the green arrow. Then, all three parts converge on one single tendon just above the elbow joint. This tendon then crosses the elbow joint and attaches to the ulna. So — when the triceps contracts — it “extends” (straightens) the elbow.
Since the origin of the “Long Head” is situated lower than the shoulder joint, positioning the arm overhead causes the distance between the origin and insertion of the “Long Head” to be farther away from each other, as compared with having the arm down at one’s side. This creates a situation whereby — potentially — the “Long Head” could be stretched more during an overhead triceps exercise. However, this requires that the elbow be fully bent, while the arm is overhead.
Exercise physiologists know that allowing a muscle to stretch more during a resistance exercise increases the potential benefit of the exercise. Thus, it’s conceivable that performing Overhead Triceps extensions COULD cause greater development of the “Long Head” of the triceps — but only the “long head”. The other two parts — the Lateral Head and the Medial Head do not change their length nor function based on the position of the arm / shoulder.
The researchers in this study acknowledged that “ALL THREE PARTS of the triceps grew more with the Overhead triceps exercise, as compared with the arms neutral (arms down) triceps exercise.”
This apparently mystified the researchers, because they know that the “Lateral” and the “Medial Heads” of the triceps do not change their length, nor their function, when the position of the arm (humerus / shoulder joint) changes. There is no logical reason why those two parts of the triceps would benefit more from an overhead triceps exercise, as compared with an “arms down” triceps exercise.
The researchers should have said, “The fact that the Lateral and Medial triceps heads improved more with the overhead triceps exercise, than with the neutral arm triceps exercise, suggests that some reason OTHER then the arm position caused the better triceps growth….maybe the better outcome was NOT due to the Overhead arm position.” Yet, it appears the researchers did not make that deduction.
The two uni-articulate triceps heads (the Lateral and Medial Heads) cannot possibly function differently during an overhead triceps exercise, as compared with a neutral arm triceps exercise. For anyone to think that an “arms overhead” position could influence the development of the Lateral and Medial Heads of the triceps, would be like thinking that if a person faced north or south — while doing a triceps exercise — that it would somehow cause a different effect on the triceps.
There is absolutely no mechanical difference in the function of the Lateral and Medial Heads of the triceps, when the arms are up versus down. In fact, there is no way for the Lateral and Medial Heads to even “know” in which position the arms / shoulders are. They only know one thing — elbow extension (and the degree of contraction / muscle shortening resulting from the degree of elbow extension).
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Exercise physiologists know that muscles have more strength potential when they are elongated, and they have less strength potential when they are shorted (contracted). This is known as the natural “strength curve” of muscles.
The triceps has more strength potential when the elbow is fully bent (i.e., because the triceps is elongated), and less strength potential with the elbow is straight (i.e., because the triceps is shortened).
Since muscles are stronger during the early part of their range of motion and weaker during the latter part of their range of motion, the BEST exercises for optimizing muscle development are the ones that provide MORE resistance when the muscle is elongated, and LESS resistance when the muscle is shortened. Therefore, selecting an exercise that provides a more perpendicular resistance at the beginning of the range of motion, optimizes the benefit to the target muscle.
All levers (which includes human limbs / bones…arms, legs, etc.) follow universal physics principles that influence how much “load” is placed on a particular structure. Longer levers magnify load more than shorter levers, and levers that are more perpendicular with resistance (e.g., gravity or the direction of cable resistance) magnify load more than levers that are more parallel with that resistance.
In the two LEFT images (both upper and lower), notice that the forearm is vertical (parallel with gravity). At both of those points in the range of motion, the triceps experiences ZERO resistance, because the forearm is parallel with resistance. The forearm is in the “neutral” position.
In the two RIGHT images (both upper and lower), notice that the forearm is horizontal (perpendicular with gravity). At both of those points in the range of motion, the triceps experiences the maximum percentage of available resistance — which is a factor of the amount being lifted.
In the TOP two images (“Lying Dumbbell Triceps Extensions”), the amount of resistance being experienced by the triceps goes from MOST (right image) when the elbows are bent, to LEAST (left image) when the elbows are straight.
Conversely, in the bottom two images (“Dumbbell Kickbacks”), the amount of resistance experienced by the triceps goes from LEAST (left image) when the elbow is bent, to MOST (right image) when the elbow is straight.
These sequential changes in the percentage of resistance an exercise delivers to a working muscle is called the “resistance curve”. Every exercise has a different resistance curve…which is part of the “biomechanical profile” of the exercise.
When an exercise has a resistance curve that matches the strength curve of the target muscle, the exercise is “better”. It provides the muscle with more resistance when the muscle has more strength capacity (in the early part of its range of motion), and less resistance when the muscle has less strength capacity (at the end of its range of motion).
Conversely, when an exercise has a resistance curve that does NOT match the strength curve of your target muscle, the exercise is compromised to varying degrees. A compromised resistance curve typically provides TOO LITTLE (or no) resistance when the muscle has more strength capacity, and TOO MUCH resistance when the muscle has less strength capacity.
Being able to recognize when an exercise provides a good resistance curve requires some familiarity with physics principles (mechanics), and this awareness is significantly different than issues related to biology or physiology.
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When evaluating the resistance curve of an exercise that uses “free weight” (dumbbells, barbells, etc.), the direction of resistance is always “straight down” / vertical. So, one would then simply compare that vertical direction of resistance to the various limb angles that occur during the exercise.
However, when evaluating an exercise that uses “cable resistance”, the direction of resistance is NOT necessarily straight down / vertical. Instead, it is the direction (angle) of the cable. For example, when doing a Lat Pulldowns, the direction of resistance is “upward” — directly toward the pulley above you. In cases such as this, you would simply compare the angle of the cable to the angle of the limb being moved by your target muscle, to evaluate the resistance curve of the exercise.
In the image below, I’ve drawn a red line through my forearm (i.e., the limb that is being moved by my triceps), and green line though the cable (i.e., indicating the direction of resistance being provided by THIS particular exercise).
As you can see, the red line and the green line are not perpendicular to each other. They are closer to parallel with each other. This means that — in that starting position (with the elbows fully bent, and the triceps most elongated), the percentage of resistance being delivered to the triceps is very small…perhaps only 15% to 20% of what it would be if those two lines were perpendicular to each other.
Therefore, this exercise (standard Cable Pushdowns) has a compromised resistance curve because it is not “early phase loaded”. Yet, this exercise — with its very compromised resistance curve— was one of the two exercises used in this study.
It is not the “neutral arm” position of a standard Cable Pushdown that makes this a compromised exercise. It is the fact that the direction of resistance is not perpendicular with the forearm, at the beginning of the range of motion.
This exercise can be significantly improved, however, by changing the direction of resistance (i.e., change the angle from where the resistance comes). By positioning the source (the pulley) behind you, you can make it “early phase loaded”. This would then provide an optimally productive resistance curve, making this an excellent triceps exercise — even though you are still using a “neutral arm” position (upper arms close to the sides of your body). In the images below, I show how you would do this.
Below is another way of doing this, with the added advantage of having “back support” and a seat, for more stability.
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The other exercise that was used in the study is depicted below — a (one arm) Overhead Cable Triceps Extension.
Notice how perpendicular the cable is with the forearm, at the beginning of the range of motion (above images, and also the image below-left). Compare this with how NOT perpendicular the cable is with the forearm, at the beginning of the range of motion, of the Cable Pushdown (below-right).
It seems the researchers thought they were comparing two triceps exercises which had ONLY one difference— the position of the arm (either “arm up” or “arm down”). In fact, they were comparing two exercises that ALSO have two drastically different resistance curves.
Consider the 4 following sets of images and criteria:
In both (left and right) images above, the humerus (upper arm bone) is vertical — in the “arms down” position and the “arms up” position. This would result in the same forearm angle relative to a vertical resistance, given the same degree of elbow bend (approximately 110 degrees). This would THEORETICALLY produce the exact same resistance curve. BUT, it is impossible for MOST people to position their upper arm to such an “UP” degree, as shown in the image above-right image. It requires that the humerus be slightly posterior to the ear. Try it now, as you read this. You’ll see that it’s extraordinarily uncomfortable — even painful — if you can manage it at all.
This means that it’s UNLIKELY the subjects in the study used this humeral position. If they did somehow manage to perform the “arms up” version this way, it must be asked “…Do you really think most people will perform Overhead Triceps Extension with this arm position, on their own?”.
Now, consider the humeral position shown in the image below.
The upper-left image shows the humeral angle which is typically used during a standard Triceps Cable Pushdown. This angle of humerus, combined with demonstrated degree of elbow bend and a vertical resistance, would ONLY produce the same resistance curve as an Overhead version (image above-right), with the same degree of elbow bend and a vertical resistance, if the upper arms were angled BEHIND the head (i.e., same 18 degree tilt, relative to a vertical). But — needless to say — positioning your upper arms at the angle illustrated in the above-right image is not possible, nor even safe to try.
Now, consider the humeral angles — and the directions of resistance — in the image below:
The image above-left shows the typical angle of the humerus used by most people when performing an Overhead Triceps exercise. This is about the maximum degree / angle of “arms up” position that most people can manage. The image above-right shows the typical angle of humerus used when most people perform a standard Cable Pushdown, as well as the typical angle of cable resistance they use (so as to not drag the cable across their face).
Notice that, in the image above-left, the forearm is perpendicular to a vertical resistance, which produces the a good “early phase loaded” starting resistance. However, the image above-right shows that the forearm would be 55 degrees less perpendicular to the cable resistance at the starting position. That is significantly less beneficial.
Lastly, consider this final comparison below:
In order to have the same degree of “early phase loading” at the beginning of the range of motion in both exercises (the same resistance curve)— using the angle of humerus that is typically (comfortably) used in both exercises — the cable resistance used in the neutral arm exercise (Cable Pushdowns) would have to come from an angle that is slightly posterior to the person.
Do you think this was done during this particular study? It’s highly unlikely.
If a study is being done for the purpose of providing people with useful information they can apply in their own workout, the study must examine upper arm (humeral) positions that people are ACTUALLY able to use comfortably, along with directions of resistance that are realistic and pragmatic. This would compare “real world” scenarios.
Concluding that an “overhead triceps” exercise is OVERALL more productive than a “neutral arm” triceps exercise, while not addressing (1) humeral positions that are typically / comfortably used by the average person, and also (2) not ensuring that the direction of resistance (relative to the angle of the forearm in the starting position) is the same in both exercises and duplicatable by the average person in the gym — is misleading.
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Therefore, I disagree with the suggestion that overhead triceps exercises are “significantly better” for overall triceps growth, compared to neutral arm triceps exercises. I concede that it is possible for the Long Head of the triceps to benefit more from an overhead humeral position. But it is not possible — mechanically speaking — for the Lateral and Medial Heads to benefit more for this change in the arm / shoulder angle.
In regard to the Long Head of the triceps, a key question to ask is this: “Can the Long Head of the triceps be adequately lengthened with a neutral arm triceps exercise, provided maximum elbow bend is used with each repetition?” I believe so, when using maximum elbow bend at each repetition.
Here’s another way of phrasing that question: “Does the triceps Long Head absolutely REQUIRE the degree of maximum stretch that can be achieved with an overhead triceps exercise ?”
There are two ways of answering this question.
One way is “Try it and see”, which is reasonable strategy. Why would you do an uncomfortable exercise (i.e., an overhead triceps exercise) if a neutral arm triceps exercise (using an optimal resistance curve and maximum elbow bend) works just as well? I am thoroughly convinced it does work “just as well”, and I have proven it with the excellent results I’ve achieved doing only neutral arm triceps exercises.
The second way of sensing whether it’s “necessary” to do an overhead triceps exercise, in order to maximally development of the Long Head of triceps, is by comparing it to the quadriceps. The triceps of the arm, and the quadriceps of the leg, are essentially the same type of mechanism.
The Long Head of the triceps and the Rectus femoris (of the quadriceps) are the only bi-articulate (crossing two joints) parts of the triceps and quadriceps (respectively). The other parts of each muscle only cross the one joint. Suggesting that it is “essential” to work the triceps with maximum shoulder extension (i.e., using an overhead arm position), would be like saying that it is “essential” to work the quadriceps with maximum hip extension (i.e., to fully stretch the Rectus femoris). In both cases— it’s absurd.
The quadriceps (including the Rectus femoris) can be more than adequately stimulated (worked) using knee extension movements that do not include maximum hip extension. Likewise for the triceps, I believe.
The two triceps exercises I most recommend are “Modified Cable Pushdowns” (using two cables, coming from behind you), and “Decline Dumbbell Triceps Extensions”…both shown below. Both incorporate an optimal resistance curve (“early phase loaded”).
You can read “The 16 Factors That Determine Exercise Value”, at my website: dougbrignole.com … which explain all the factors that can be used to determine the value of an exercise.
I have deliberately avoided overhead triceps exercise for the past 20 years, and — as you can see below — my triceps development have not been the least bit compromised…not even the “Long Head”. In addition, the numerous clients I have coached, as well as those who have followed the recommendations in my book, have also reported exceptional triceps development doing only one of the two triceps exercises shown above (both being “neutral arm”). This is empirical (real world) evidence.
THE BOTTOM LINE:
The conclusion reached by the researchers who conducted this study…
“Triceps brachii hypertrophy (growth) is substantially greater [using overhead elbow extension versus neutral arm elbow extension]”
…is misguided and misleading.
The outcome of this study would have been very different if the “arms down” triceps exercise used in the study had used an optimally productive resistance curve (i.e., a perpendicular direction of resistance at the “early phase” of the range of motion), instead of the compromised resistance curve which is typical of a standard Cable Pushdown.
This is not meant to suggest that Overhead Triceps Exercises are “not productive”. They can be productive, but are not superior to “neutral arm” triceps exercises which are early phase loaded.
It is possible that the triceps’ Long Head would benefit more from an “arms up” triceps exercise, provided the elbows are fully bent at each repetition. But this does not necessarily mean that Overhead triceps exercises are “essential” for optimal development of the triceps’ Long Head.
The Long Head of the triceps can be very adequate stimulated using “arms down” (neutral arm) triceps exercises, provided the elbows are maximally bent with each repetition, and the exercise is early phase loaded.
Click on the image above for a larger view.
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Doug Brignole has been studying biomechanics as an independent scholar for the past 30 years. He is a veteran competitive bodybuilder with over 43 years of experience, a former Mr. America winner and twice Mr. Universe winner, and a respected author. His book (“The Physics of Resistance Exercise”) has been endorsed by numerous PhDs in biomechanics, exercise physiology, physics, evolutionary morphology, bioengineering, bio-robotics and neurobiology, plus several orthopedic surgeons. He is still competing successfully at the age of 62 — without injury.