Panel Discussion: Can we target different sections (upper, lower, origin, insertion) of a muscle?
Moderated by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS
This discussion originally started as a post on my facebook page (https://www.facebook.com/brent.brookbush ) that featured a snippet from my book "Fitness or Fiction: The Truth About Diet & Exercise" and addressed the lower ab myth.
A discussion between myself and Human Movement Professional Joshua Morton (https://www.facebook.com/joshua.morton.98 ) unfolded beautifully, asking all the right questions. So here it is - See the original posting below:
Snippet from "Fitness or Fiction: The Truth About Diet and Exercise" by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS
http://www.amazon.com/Fitness-Fiction-Truth-About-Exercise/dp/0615503012
“Myth #29: You can work your lower abs.
What You Should Know: There is no such thing as lower abs.
One of the largest myths in the fitness industry is whether or not you can target the upper or lower portion of your abs. Allow me to destroy this myth right now. All muscles contract from origin to insertion. That is your abs, when activated, will always contract across the whole length of the muscle from pelvis to rib cage. The muscle must contract across its full length to act on your spine effectively. You would never think of working your lower bicep or lower glutes, so why your lower abs? Imagine…"
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Joshua Morton True you cannot isolate one belly from another or origin from insertion. But, you can change how the tissues based on placement of fulcrum and load and of course the god of exercise, form..
May 27 at 6:06pm
Brent Brookbush I don't know if I understand the point Joshua Morton - if the muscle generates force across its entire length how can we change the stress on any one section of this muscle, and how would that affect adaptation. I have to be honest, I am really not sure why this myth is so pervasive - we don't attempt lower bicep work.
May 27 at 7:51pm
Joshua Morton If we do shoulder flexion we are targeting the "origin" of bicep, if we do elbow flexion we are targeting the "insertion" of bicep. Of course when we do either of these movements we are targeting everything that does the movement. But if the shoulder insertion of bicep is damaged we will never make it strong again by flexing the elbow. In regard to the abs, it is my view, from anatomy, that the abs, except the lower bellies of rectus, terminate at the arcruate line. If the load is not delivered below this point we are emphasizing upper bellies and obliques primarily. By the time the torso flexion reaches the point of the division of the tissue (via the arcruate line) it is very difficult to "turn on" the lowest portion of the rectus. Also, when the load is on the top the pyramidalis gets less attention. I do agree that everything along the line of movement is working, however, based on my own exercise experience and clinical outcomes I stand by my statement. I have had many clients who have been through the standard PT exercises. And when I adapt them in these ways the difference is felt immediately.
May 28 at 11:53am
Brent Brookbush There is a physiologic and physics problems with your first statement Joshua Morton. Just because we do shoulder flexion does not mean that the biceps works from origin to insertion. In fact, the impetus to flex the shoulder is going to result in a motor pattern being "activated" and the neural impulses will be sent by way of the motor nerves. The nerves that initiate contraction of the bicep actually invest in the bicep at the motor endplate, very close to the center of the muscle belly. All contractions "start" at these motor end plates… in essence it does not matter whether you do elbow flexion or shoulder flexion - the signal goes to the same place.
From a physics perspective your argument would be akin to tying a rope to a truck and then attempting to pull on that rope in such a way that more force is applied to the end of the rope that you are pulling on versus the end of the rope tied to the truck. If tension develops along that rope it will develop evenly. This transmission of force is necessary to impart force on the truck and do work. As far as the abs… think about the rope and truck example… it just don't make sense.
May 28 at 8:46pm
Joshua Morton I understand the neurologically everything fires. What I am looking at is levers and pulleys. Depending on where you place these, the load changes on that rope. We might not be able to lower the piano down from the second flow on our own with the rope, but with a good lever and pulley set up we can. Hence cams placed in machines.
Wednesday at 11:42am
Brent Brookbush But that does not mean there is an uneven amount of resistance on the rope, especially in terms of a single pulley system, and we have very few pulleys and far more levers in the musculoskeletal system.
Wednesday at 6:31pm
Joshua Morton ok, I can buy that, but more on the bicep. Bicep also flexes the shoulder and if you want to strengthen or perhaps it is better to say neurologically return its ability to flex the shoulder, how is flexing the elbow going to help with that portion of its action?
Wednesday at 9:25pm
Brent Brookbush I think the answer lies in the synergistic recruitment of all muscles at the joint you are trying to work. I doubt the biceps alone would be very effective at flexing the shoulder (although it may supinate the forearm without ancillary muscles). In essence, when you are training a muscle to work at a particular joint, the muscle does not fire different, but the timing with which it is fired and the number of motor units recruited may vary quite a bit depending on the task.
Wednesday at 9:37pm
Joshua Morton Understood, but either I am confused or something else. Hypothetically, MRI shows conclusive tear in bicep tendon "origin". Of course every shoulder flexor is going to help in the action but if you only work on elbow flexion the torn tissue will never restabilze.
Wednesday at 9:43pm
Brent Brookbush No, but it will "scar down" or need primary repair (surgical fixation) and then "scar down." Chances are we see the majority of tears at the proximal biceps tendon due to it being smaller in diameter than the distal attachment, its attachment to primarily soft tissue (the glenoid labrum), and likely the most influential factor is long term cumulative damage to the tendon from impingement between the subacromial shelf and the greater tubercle of the humerus (impingement syndrome).
Wednesday at 9:48pm
Joshua Morton That I more or less totally agree with Brent. Ive ben fortunate enough to help patients get through these problems without surgery. Not all mind you. I am not claiming a cure or anything like that. But the work I utilize can be very helpful. Im sure no different than you and the work you do.
Thursday at 11:41am
Brent Brookbush For sure Joshua Morton… Surgery is a last resort. There is a tipping point in which surgery is the best option, but that generally implies that without surgery the long-term impairment is worse than the potential damage of surgery and the risks associated with it. It is our job to keep pushing back that tipping point, and when at all possible (and I believe this is where we can have the biggest impact), prevent the impairment that would lead to an injury worthy of surgery to begin with. Research on surgical outcomes is actually tipping the scales in our favor and has been a wonderful tool for promoting conservative treatment (therapy over surgery).
Thursday at 6:53pm