Review of Questionable Conclusions
of Scientific Studies (a series)
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 did one of the exercises with their left arm, and the other 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.
Actually, 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” to the overhead arm position. However, the “neutral arm” exercise they selected for the study, has a very compromised resistance curve. The “overhead” exercise they selected has a much better resistance curve (i.e., the direction of the resistance is more perpendicular to the forearm, at the beginning of the range of motion). So, the exercise that was more productive was the “overhead” exercise, but that was more likely to due to the fact that the “overhead” exercise had a better resistance curve than the “neutral arm” exercise.
The resistance curve of each exercise was not even addressed, so it appears to have not been considered.
In order to accurately assess the value of a “resistance exercise”, a researcher must have a thorough understanding of the mechanics that occur outside the body (i.e., the physics of each exercise), and ensure that both exercises being compared have the exact same resistance curve — thus eliminating all possible confounding variables.
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), 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, 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 riceps exercise. However, this requires that the elbows be fully bent, while the arms are overhead.
It is well known among students of exercise physiology 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”…not the other 2 parts.
The researchers in this study noted 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 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. Therefore, 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.
Yet, apparently none of the researchers stated, “…the fact that the lateral and medial triceps heads improved more with the overhead exercise suggests that some OTHER reason probably caused the better triceps growth….maybe the better outcome was NOT due to the Overhead arm position.”
The two uni-articulate triceps heads (the lateral and medial heads) cannot possibly function differently during an overhead triceps exercise, because their length is not altered — in fact, nothing about their function is altered — by a change in the shoulder angle. So this was a clue that something ELSE caused the triceps to grow better with the overhead triceps exercise.
In fact, the direction of resistance typically applied during an overhead triceps exercise is MORE PERPENDICULAR to the forearm, then that which is typically applied during a standard Cable Pushdown. This results in a more productive resistance curve with the overhead triceps exercise, then the compromised resistance curve of the standard Cable Pushdown. This is the only plausible reason why the uni-articulate triceps heads developed less well with the Cable Pushdowns.
In order for the conclusion of a study to be accurate, the researchers must be aware of how and when OUTSIDE forces (ground reaction force, centrifugal force, centripetal force, friction force, composite force, momentum, varying DIRECTIONS of resistance and variations in “moment arms”) are occurring. It seems this was overlooked in this study.
Students of exercise physiology 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 “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. Selecting an exercise that provides a more perpendicular resistance at the beginning of the range of motion, optimizes the benefit to the muscle.
All levers (which includes human limbs…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) magnify load more than levers that are more parallel with resistance.
In the two LEFT images (upper and lower), 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 vertical (in the “neutral” position).
In the two RIGHT images (upper and lower), 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, and 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, and 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, or “biomechanical profile”.
When an exercise has a resistance curve that matches the strength curve of your target muscle, the exercise is GOOD. 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).
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 physiology.
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 varying limb angles 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 of the cable. For example, when doing a Lat Pulldown, the direction of resistance is “upward” — 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., 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 elbow 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 compromises this exercise. It is the fact that the direction of resistance is not perpendicular with the forearm, at the beginning of the range of motion. It can be improved, however. If you were to change the direction of resistance (i.e., change the position from where the resistance comes), you can make it “early phase loaded”. This would then provide an optimally productive resistance curve, making this an excellent triceps exercise. In the images below, I show how you would do this, even though the arm motion stays the same. Make the resistance come from slightly behind you, rather than from in front of you.
Below is another way of doing this, with the added advantage of having “back support” (and a seat) for more stability.
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, and 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”). But, they were comparing two exercises that ALSO have two drastically different resistance curves.
Acknowledging when the direction of resistance is perpendicular to a limb — versus parallel to a limb — is critically important, because only then can the “resistance curve” of the exercise be identified. Only then can it be determined whether it matches the strength curve of the target muscle. Only then can a comparison between two exercises be accurate.
The conclusion reached by these researchers — that “Overhead Triceps Exercise are more productive than Neutral Arm Triceps Exercises” — ignores the significant difference in resistance curves, between the two exercises.
I believe it’s entirely unreasonable to suggest that overhead triceps exercises are “significantly better” for triceps growth, compared to neutral arm triceps exercises, which was the conclusion of this study.
The lateral and medial heads of the triceps are not the least bit altered in their function, based on the position of the arm / shoulder. Therefore, it should be clear that these two parts of the triceps CAN be optimally developed with any triceps exercise (any arm / shoulder position) provided an optimal resistance curve is used (early phase loaded / perpendicular resistance at the beginning of the range of motion).
In regard to the long head of the triceps, the key question — I believe — is: “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?” In other words, “Does the long head absolutely REQUIRE the maximum stretch that could be achieved with an overhead triceps exercise AND maximum elbow bend with each repetition?”
There are two ways of answering this question.
The first way is “Try it and see”, which is a very reasonable strategy. Why would you do an uncomfortable exercise (i.e., an overhead triceps exercise) if a neutral arm triceps exercise (with 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. The thought that “I cannot achieve optimal triceps long head development UNLESS I perform an overhead triceps exercise” seems absolutely ridiculous to me.
The second way of sensing whether it’s “necessary” to do an overhead triceps exercise in order to achieve optimum development of the triceps long head, 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 parts of the triceps and quadriceps (respectively) . The other parts of each muscle only cross the one joint. The suggestion that training the triceps with maximum shoulder extension (overhead position) is “essential”, is like suggesting that maximum hip extension is “essential” when working the quadriceps (i.e., to fully stretch the rectus femoris). In both cases — I believe — it’s absurd.
The two triceps exercises I most recommend (the only ones I do…one or the other, but not both, per workout) are “Modified Cable Pushdowns” (using two cables, coming from behind you), and “Decline Dumbbell Triceps Extensions”…both shown below. Both have an optimal resistance curve.
You might want to read “The 16 Factors That Determine Exercise Value”, at my website: dougbrignole.com …in order to see 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 has 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 options shown above.
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 had 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 when they 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 mean that “overhead” triceps exercises are “essential” for optimal development of the triceps’ long head.
The long head of the triceps can achieve very adequate stimulation with “arms down” triceps exercises, provided the elbows are maximally bent when performing “neutral arms” triceps exercises, and the exercise is early phase loaded.
Doug Brignole is a veteran competitive bodybuilder with over 43 years of experience. He is a former Mr. America and twice Mr. Universe winner, and a respected author. He is still competing successfully at the age of 62 — without injury.