Science vs Anecdotal Evidence

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Recently I was scrolling through my facebook feed, seeing posts about new PR’s, holiday meals, and excitement about the new Star Wars movie.  I came across a post from another fitness professional who is very well read and educated and whose opinion I respect.  He said:

Don’t understand why lifters perform reverse grip triceps pressdowns. The triceps attaches at the ulna, so supination has no effect on the muscle. And a reverse grip increases the demand on the hand/wrist muscles to maintain the grip, which ultimately reduces demand on the triceps.

That struck me as odd.  I have performed and programmed in reverse grip tricep pulldowns in many programs to emphasize the long head, I thought it was pretty common knowledge that you could emphasize one head of the triceps over the other.  I chatted with him about this for a bit online and I asked for further clarification and his opinion was that it didn’t matter if it was a v-grip, a rope, a straight bar or a reverse grip, if the upper arm was in the same position you would hit the same heads equally.

First, we can examine this specific issue of how to train the triceps; but really I think this is a good example to see how one looks at things in a broader way and that is the main thrust of this article.

What does the science say?

If you ask the specific question: how does varying your grip affect the tricep head activation in pushdowns, the science doesn’t really say anything.  To be clear it is not saying you can activate one head over the other, it is not saying you can’t; to my knowledge there are simply no detailed studies that explore this and provide a reasonably definitive answer.

Why would one believe grip doesn’t matter?

There is a huge “scientific” reason why one might believe that the grip doesn’t really matter and it is this.  The insertion (end point) of the Triceps Brachii tendon is the olecranon process of the ulna.  This is the fancy name for your elbow.  Put your fingers on your elbow right now.  Now swivel your hand (supinate and pronate it).  You will notice your elbow does not move at all no matter what your hand does.  So the logic is if the ulna can’t move and the tricep doesn’t cross the wrist, then hand position doesn’t matter.  Some would go so far as to say that is what science says period and anything else is “broscience.”

What evidence is there that changing the grip matters?

I don’t believe it is an open and shut case just because the above fact is true.  The human body is made up of patterns, muscles in our upper body mimic those found in our lower body.  The triceps is analogous to our quadriceps (the anconeus would be the left over 4th head), just like our biceps is analogous to our hamstrings (which are sometimes referred to as the leg biceps).  We do know for sure that you can emphasize one part of the quad over the other by focusing on a certain part of the range of motion (lateralis works more when the knee is fully flexed, medialis works more at the end of the ROM).  It may be that foot position and stance width affects those muscles as well.  The quads are just like the triceps, all quads go and insert into one spot and that spot would move minimally no matter what leg exercise you were doing.  So there is a precedent that you can emphasize a certain head in one muscle over the other based on exercise selection and technique.

Then there is the simple fact that we have 3 heads.  The body is pretty lazy, it doesn’t have secondary systems for no reason.  Science is pretty clear that you can emphasize the long head by changing the position of the humerus (go over your head into shoulder flexion to stretch and activate it) but that still leaves the medial and lateral head.  Why would we have two heads, in distinctly different parts of the arm and generally different size from each other, if they had the same function?  Why wouldn’t we just have one muscle there instead?

There is additional evidence that the 3 heads, or even just the medial and lateral heads (the one joint muscles) don’t function as a single unit.  Here is one excerpt from a scientific article showing that the three heads had separate fatigue rates in the same task.  This article doesn’t tell us how to work each head, but it does tell us the heads fatigue at different rates and the triceps should not be viewed as a single unit.  To me that sets the stage for the debate which is then what is the best way to hit each part of the tricep:

Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863), followed by the medial head (slope = −2.412) and the lateral head (slope = −1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads. [source]

 

There are bunch of different grips available.  It would seem odd to me that someone would have gone through the trouble of actually making a v-grip, a rope, an EZ bar, a straight bar, a wide rope, etc if there was no difference.  And for essentially every gym to have those various tools must mean it is something that trainees have found a value in.  Why invent and then keep making and selling these things if there truly was no difference at all?

It only takes a cursory look at gym members, bodybuilders, and your own arm to realize the heads don’t respond the exact same.  Some people express well developed long heads, others have impressive lateral heads, some have impressive medial heads.  Not everyone is the same.  If you could not separate out the lateral and medial head through activity how could there be a difference?

The feel test, meaning what trainees feel is working when doing the exercise, is very strong and many people can feel the difference in the heads working on various grips.  While I certainly want to promote a rigorous scientific approach to most things, I almost feel like the pendulum has swung too far and if someone says “I feel it there more” we just shake our head and look at that person like they are a confused 4 year old.  If a total newbie reports feeling an area, particularly if the area isn’t even involved, obviously we will take that with a grain of salt.  But if a serious trainee with lots of experience comments that a particular exercise makes them feel a certain area or muscle much more, that is evidence to consider.  I am not arguing that it is the end all be all but it should not be dismissed or carry no weight.  I know when I use the various grips I feel the different parts of the muscles working.  Could I be wrong or could I be interpreting the signals incorrectly?  Of course.  But does that mean it carries no weight or that I can’t learn from that?  Hell no.  It absolutely is valid to consider that information, it is one piece of evidence, nothing more, nothing less.

The weight lifted on the various exercises will differ significantly.  The rope is always the hardest (when done with proper form), V-grip is usually the strongest, with straight bar and the reverse grip falling somewhere in between.  The medial head is the smallest and the weakest so it would make sense that the exercise that emphasizes it (the rope) is the hardest.  Note the medial head is key in the lockout (again I think you can feel this pretty easily – palpate your medial head by finding the bony knob on the inside of your elbow, move up about 2-3”, and really contract your tricep.  Take a note of how hard it is, then forcefully extend your elbow and note how much harder it is), but if you want a more scientific view point the medial part of the quad (Vastus Medialis) works the most in the lockout portion so it would make the sense that this part of the tricep would be involved in the lockout of the arm.

A simplified way to look at anatomy is that we are puppets and the muscles are our strings.  Pull a string in a certain way and we move in one direction, pull a string in another and we move in another.  A multi-headed muscle is like having several strings that all attach at the same point.  If you want a muscle to work optimally you want to line the muscle up with the angle of its fibers and the joint.  For example a bicep is much stronger when you curl in front of you (in the sagittal plane) then when you externally rotate your arms so that your forearms are sticking out at a 90 degree to your body (in the frontal plane).  Your triceps essentially has 3 strings.  If your elbow is kept tucked in and inline with your forearm and your arm is extended your long head is generally put in the best line.  A reverse grip is an optimal way to do this.  If your elbow flares out but your hands stay narrow and you want to extend your elbow now your lateral head is in a good line to pull (as in a V-grip pushdown).  And the medial head does best at the end of the ROM when you need to flare and lockout the elbow, particularly with a pronated grip (as in a rope pushdown).

Finally I believe this hypothesis (that different heads of the triceps work in different positions) correlates well with what we see when people perform compound movements.  In the ideal bench press you want to tuck your elbows on the descent and control their flare on the press up.  Doing so will activate the long head more which has the potential to be the biggest and thus the strongest head of the triceps.  (Personally when I am looking to see if someone is a studly bencher I look for a thick chest, shorter arms, and a giant long head of the triceps).  If you flare out your arms too much or too soon you will place more emphasis on the lateral head which is generally weaker, although in my opinion is easier to develop for some people.

In my opinion there is a very large amount of anecdotal evidence that is strong enough to suggest that it is very likely that altering your grip on tricep pushdowns does result in change to the part of the muscle stimulated from the exercise.  But really this represents a bigger picture, which is the way one looks at the ‘scientific’ and the anecdotal evidence available.

Some, like my colleague, may tend to take a “science must prove it” attitude.  The logic being that there is some evidence that grip doesn’t matter (since the ulna doesn’t rotate) and until there are clear and concise studies showing there is a difference, he will be comfortable believing there is not a difference.  A good question for these people is how much anecdotal evidence do you need to believe in something?  If one chooses to ignore all anecdotal evidence then I think one is really limiting their field view and the sources they can learn from.

Others may tend to take more a “science needs to disprove it” approach.  The logic behind that is we do have a good amount of anecdotal evidence to think a certain way, and we will probably believe that until we are disproven.  A good question for these people is how much science do you need before you stop believing in something?  If it is a huge amount you run the risk of the being extremely stubborn or even almost fundamentalist in your approach and that is more often a negative than a positive.

There are pros and cons to both approaches.  In the former, the good news is that you will usually have reasonable evidence before drawing a conclusion and you are not likely to fall for too many myths and things that are total BS (which is rampant in the industry).  However the negative is sometimes those that feel they are “grounded in science” feel firmly that they are right once they have looked at the evidence and they can be dismissive of other viewpoints.  The classic example of this was 2 decades ago we learned you can’t just isolate a certain part of a muscle and everybody went around saying that there were no “upper” or “lower” abs, it was all one muscle and the whole thing was always working.  Indeed that was like the dividing line among those who really studied and knew their stuff and those were just the gym bros who didn’t know anything.  Then of course, later on we learned that you can emphasize parts of a muscle (particularly when fibers start and stop at tendinous cross sections) and you can emphasize your upper abs more or lower abs more (and anyone who had experienced a cramp in just one part of their rectus abdominis already knew this) and now you sound like an idiot if you run around telling people you cannot focus on upper or lower abs.

The benefit of taking a “science needs to disprove it” viewpoint is that you don’t have to wait for science to study it before taking an opinion.  You can trust yourself and focus on the results that you do get.  However you have to do your best to factor out any biases or misinformation you have and even after you do that you have to realize you can never fully do that and you are more likely to believe something false, you might be spewing forth some bullshit from time to time, and you should be open to change when new information presents itself.

It is also worth mentioning that being wrong on an issue doesn’t make you an idiot.  If my friend is wrong and you can emphasize one part of the tricep over the other, he might be wrong about this issue but that doesn’t make all of his other work suspect.  If I am wrong and you can’t emphasize one part of the tricep that doesn’t mean I am idiot either.  It is one issue (and in this instance a relatively small one).  In my experience people would do well to remember that no matter what anybody is saying, they are really saying “I believe…” in front of their thoughts.  There are very few things that one knows with certainty.  So just remember when you read that next tweet you don’t like, or one of your friends posts some dumb political comment on FB, they are really saying “I believe that ….”  You can simply say, “well, I believe this ….” And you might be different and that is okay.  Remembering they are just stating a belief, even if seems disguised as a fact, might help lessen a strong emotional reaction from you.

What did I learn from this?  There is less scientific consensus on this topic than I thought.  Based on the evidence above I would still feel comfortable telling someone how to target their long, medial, or lateral head but I would preface it by saying: The science is not super clear but there is significant evidence to suggest that X, Y, Z exercises will target the various heads in the tricep.

After delving into the issue more I would hope my colleague would say: There is anecdotal evidence that suggests that X, Y, Z exercises target the various heads of the tricep but there is not a scientific consensus about it.

And sometimes when you more fully explore an issue you realize you are not as far apart as one initially thought.

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One thought on “Science vs Anecdotal Evidence

  1. Pingback: Science vs Anecdotal Evidence: How to Train Your Triceps

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