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Tuesday, June 6, 2023

Hip Activation

Brent Brookbush

Brent Brookbush


Panel Discussion: Hip Activation

The Hip: What muscles are prone to under-activity and what exercises do we use to activate them? I know experts Eric Beard , Marty Miller , Alan M. Russell , Rodney Corn , and Derrick Price have an intense amount of knowledge on this subject. Special thanks to Blake Robinson for the idea for this week’s discussion.

Moderated by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

This Panel Discussion was originally posted on my facebook page - https://www.facebook.com/brent.brookbush - on June 21st 2010

Marty Miller, June 21, 2010 at 12:45pm: Well I will start the conversation of with the obvious. The glute max and glute medius seem to be under-active in many individuals. And their movement compensations could be all different. From there depending on the movement compensation we are seeing other muscles like the piriformis or deep hip rotators tend to be under-active.

The adductor magnus, hip flexor complex in most positions, and TFL tend to be generally overactive.

Now this is a very broad way to answer the question that was posed, but I thought I would start it off in a general sense and something tells me we will all get into a lot more detail as we go.

Brent Brookbush, June 21, 2010 at 12:50pm Great points Marty, So let’s list our underactive structures, from most likely to shut down to rarely shuts down.

1. Gluteus Medius

2. Gluteus Maximus

3. Deep External Rotators of the hip (Piriformis, Gemelli, Obturators, Quadratus Femoris)

4. ?

5. ?

6. ?

Matt Schoeneberger, June 21, 2010 at 7:28pm: What about psoas? It seems it's often tight, but is it underactive/weak as well?

Brent Brookbush, June 21, 2010 at 10:42pm: Hey Matt,

This a really important question, and leads into a fundamental concept of corrective exercise. Short muscles are also weak… but they have a tendency to be overactive. It is theorized that muscle length not only effects cross-bridging, but the excitation threshold of muscles as well. So while short muscles are weak they are activated to easily, and often prematurely. Although it may logical to strengthen all weak structures, the lengthening of short muscles decreases there excitation threshold, and returns them to optimal length leading to optimal force production, and recruitment respective to muscle synergies. This improvement in mechanics will often lead to better function of short muscles without any specific strengthening.

Now, back to the psoas. It is rare that the psoas is long and in need of activation. I have known only a handful of individuals in this situation. Your assessment of their posture would show a reduction in lumbar lordosis and/or a posterior pelvic tilt. My girlfriend, and NASM's own Rick Richie are two of the handful of individuals I have known that have benefited from a hip flexor strengthening programs, including exercises usually frowned upon like roman chair leg raises, sit-ups, and stability ball pikes.

Derrick Price, June 21, 2010 at 10:54pm: If a muscle is "underactive", is it underactive in all 3 planes of motion? How about with over-activity?

Brent Brookbush, June 22, 2010 at 12:32am: Yes, it is underactive in all 3 planes. Under-activity is not a function of planes, unless you can preferentially recruit a motor unit that is plane dominant. This is unlikely… I think in certain cases sections of a muscle are so plane dominant that adaptive shortening may predispose certain motor units, i.e. the anterior fibers of the gluteus medius, but we are treading on some shaky territory. Muscles are simply motors that turn on, and turn off, they can't think.

Derrick Price, June 22, 2010 at 9:27am: When one plane of motion is dysfunctional for whatever reason, the body will choose a different plane of motion to move into to compensate. So a glute may not fire as readily as it should in the sag plane (because maybe there is restriction at the ankle) but it may fire and cause transverse/frontal plane to avoid the sag plane.

When does a muscle have a readiness to activate: the shortening or lengthening period? To fully function, a muscle load to unload, lengthen to shorten, so if I were to load a muscle tissue to enhance it's up-regulation, I would lengthen it to place more load through the tissue and "wake it up". So for example, the right glute, I could have the person squat but then perform a reach with the left hand to the right knee to load it even further (activate the posterior oblique system). Traditionally we focus on activating a muscle during the shortening period but we forget how muscles can activate eccentrically and isometrically as well. And typically we must eccentrically load a muscle before we get it to concentrically contract during movement.

I disagree that muscles simply turn on and off. This is a very isolated view of how muscles contract without considering the contractile properties of the fascial tissue that surrounds them or how muscles work in concert with each other (muscle synergy) to create motion. Instead of a light switch that turns a light on or off, think of a dimmer that can change the brightness of the light. If the muscles did turn on and off, think about what walking would look like? We'd look very robotic! If you have the DVD made by Primal, they show the activation of muscle tissue during a walk and you'll see how muscles become more or less bright but may not necessarily completely turn off (depending on the movement and where they had their EMG hooked up to).

Brent Brookbush, June 22, 2010 at 1:12pm: I am with you for most of it, but we view the activation of muscles differently. If a muscle cannot act in its dominate plain it will lead to inhibition, relative flexibility, and synergistic dominance (see Sahrmann). For example, if your glute max is inhibited, due to sagittal plane restriction (tight psoas), it is still inhibited in the frontal and transverse planes, increasing our reliance on proximal joint mobility, and compensatory motion. In the example above, this would lead to dominance of the deep longitudinal subsystem, and increased motion of the lumbar spine, and pelvis (respectively).

It does not matter how you load the glute, until you have removed the restriction, and decreased the hypertonicity. Returning to the example above, reaching for the opposite knee is only going to load the biceps femoris and reinforce the compensatory movement pattern.

On connective tissue… we may be arguing over syntax, but fascia does not contract. I know this has been popularized in the last few years with the increase in awareness of the importance of fascia, but there are no contractile fibers capable of creating motion in connective tissue. In muscle tissue, highly organized actin and myosin filaments are arranged to pull one closer to the other. A quick look at any physiology text will note that his is a unique property of muscle tissue, and is not evident in any other tissue to the same extent.

Connective tissue is elastic… the only motion caused by fascia is an "elastic recoil" to its resting length. You can load connective tissue to increase force production (i.e. plyometrics), but this is not the same as shortening from a resting length. The fascia is a support system, that may have deleterious effects on performance is restricted, but we cannot forget about the nervous system, muscle system, and the largest "connective tissue system" - bones and joints.

Further, the term up-regulation in your post has found a new meaning… As I understand it up-regulation and down-regulation is a process of the cell, increasing or decreasing hormone receptors in response to an "imbalance" in hormone levels. For example, extreme amounts of insulin will cause a cell to "lyse" or destroy intermembrane receptor proteins to decrease sensitivity (i.e. diabetes). There is no evidence that I know of that eludes to a stretch or activity being able to instantly change the up-regulation or down-regulation of muscle cells to hormones, and fascia… well the parts of fascia that everyone is discussing are not cells themselves.

Brent Brookbush, June 22, 2010 at 1:18pm: Last point, I think the dimmer switch on muscles analogy is a little inaccurate. I think we could view a muscle as having multiple light switches for the same room (similar to all the switches for all the lamps in your living room), but there is no dimmer. Motor units either fire or they don't. The number of motor units that fire determines force production (i.e. the all-or-none principle). So in terms of the robotic movement… it's the number of motor units recruited and not the level. The reason this is important goes back to our first comments regarding movement… A muscle cannot decide which plane it will activate in, unless the differentiation of motor units is dependent on planes. This is once again a tough call…

Jonathon Schetzsle, June 22, 2010 at 1:21pm: Great stuff guys! Very enjoyable and educational following along!

Derrick Price, June 22, 2010 at 2:05pm: I'll guess we'll have to disagree then for the time being because from my understanding, a muscle may become inhibited in one plane of motion, doesn't mean it will be inhibited during movement in other planes. Muscles may be antagonistic in one plane of motion but synergistic in others so a muscle can still have the ability to activate when creating movement in a different plane.

Also, we discussed fascia a few weeks ago and in that discussion Rod provided evidence that fascia does in fact have contractile properties and can substantially transmit force.

We have different views on how muscles activate which is why I use the term up and down regulation. It is not a term merely used for cell processes'. I can activate or place more stress through the quads during a squat if I so choose by simply raising the hands above the head. Hold the bottom of your squat, then raise the hands slowly overhead and then bring them back down. Doing so places more stress through the superficial front line (anterior tissues of the body) so is this a case of turning on more muscle fibers of the quads or that I'm simply up-regulating the quads by putting more fascial tension through them or both?

Force production is not determined solely by number of motor units recruited. There are numerous things to consider such as muscle synchronization and connective tissue pliability to name a couple.

Rodney Corn, June 22, 2010 at 2:13pm: Interesting…

Brent, to be a bit more accurate, you may want to investigate the properties of fascia. Most researchers (who research fascia) believe it does contract and does have contractile properties - not the same as muscle, but it does have unique properties capable of contraction AND communication outside of the nervous system 'control' …

Also, when discussing weak, inhibited, tight, restricted, etc. it may be important to discuss WHY these tissues get this way..? Meaning, the neurophysiologic mechanisms behind these terms… I think it is very important to remember if a muscle cannot shorten properly, it will often test weak and this can create a feeling of 'tightness' in an 'opposing' muscle - so weakness can definitely cause the tightness via spindle (gamma loop) dysfunction and tightness can perpetuate weakness… They work together.

Typically, in your educational process (which I am very familiar with), it is always stated that tightness causes weakness (based in large part on some of Janda's & Sarhmann's work) and that can definitely happen, but it is also important to note that weakness can cause tightness and in fact can happen a lot more than has been given credit for. This takes us back to the intrafusial fibers of the MS… if the gamma loop is not able to keep the MS in sync with the extrafusial fibers (muscle), than the muscle will not shorten and this creates instability in the joint. Instability as you well know creates 'tightness' - a protective mechanism. This essentially raises the muscle's threshold to activate appropriately and is what is often termed 'inhibited'… inhibited = raised activation threshold.

Also, when a muscle (extrafusial fibers) is not operating at optimal levels (weak, inhibited), the joint axis is 'thrown off' and this results in altered mechanics and leads to what you would call 'synergistic dominance'. All myofascial tissues surrounding a joint must be able to sustain a certain level of 'activation' (or tension / tone) regardless of direction of resistance or motion involved (think of it like a tug-o-war and this is where fascia plays a huge role in transferring forces through the system to maintain 'tension'). This is why it is just as important for a muscle to shorten properly as it is to lengthen properly. If some muscles do not shorten properly, cohesive tension will not be maintained and the instantaneous axis of rotation will be lost = instability = inhibited = tightness/protective mechanism

So weakness resulting from inability of muscle (extrafusial fibers) to shorten due to the MS (intrafusial fibers) inability to remain in sync with extrafusial fibers can definitely lead to tightness – over-activity.

NOW, where does the weakness come from… well, inflammation is a great place to start. It can play a massive role in the whole weakness / tightness issue. And what causes inflammation… :/ I think you know the answer to that, don't you…? ;-)

So, that being said, it is really weakness / tightness that needs to be addressed or are these symptoms of something larger that we rarely pay attention to yet discuss all the time…?

Brent Brookbush, June 22, 2010 at 3:11pm: Great points Rodney,

I am with you on everything… I have definitely noted weakness leading to tightness, the effects of the inflammatory process, and the problems with generalization of tight, weak, underactive, overactive, short and long as terms unto themselves. However, the generalization of these terms is relevant to pedagogy. Without the understanding of short and long, dyskinesis of joint structures is hard to introduce much less understand. Without understanding overactive and underactive it can be hard to visualize the impact the nervous system can have on the human movement system. So while I agree with all of your points and practice many of them, I see the value of these terms in the initial stages of learning - and am almost certain you do as well, as you are an incredible teacher.

Where I diverge in opinion is…. in your statements above I do not see a clear argument for muscles being weak in one plane, and not in another. Although dyskinesis of a joint can lead to impingement of connective tissue in one plane and not another, and this may result in reflexive inhibition of a muscle, this is not the same as saying a muscle is weak in one plane. And, the effect this has on practice has little to do with planes and far more to do with muscle balance, in an effort to return normal arthrokinematics. For example, if the hip capsule is impinged during flexion causing "weakness", working the psoas in the sagittal plane (or any other plane for that matter) will have little if any impact on the inhibition created by impingement. To interject about fascia - fascia may have to be addressed to correct this or any other movement dysfunction.

Where I am mystified… The "contractile ability" of connective tissue. In fact the elastin, collagen, and ground substance that everyone refers to in connective tissue is not even alive. The cells that produce them are capable of movement via the microtubules, actin and "motor" molecules within them, but they only produce enough force to move the cells themselves around. I have returned to my physiology books, have referenced other texts and can find nothing that would even imply the contractile ability of this tissue… The closest I could get in my own thoughts was relative dehydration of the connective tissue matrix… but this is hardly "instant".

Derrick Price, June 22, 2010 at 3:35pm: I hear ya Brent, my world flipped when I started hearing about fascia's ability to contract and transmit force. Unfortunately this information is so new you won't find it in a physiology text (that I'm aware of) but rather in the most recent research. I wouldn't doubt though that future phys texts will explore this information.

Brent Brookbush June 22, 2010 at 3:41pm: I appreciate the empathy, but I want more than that. I am fine with information that is so new it is not in current texts, and lacks a robust body of research, but there has to be a sound theory behind these statements. At this point, I am not only missing information, I have yet to hear a theory that backs up the claim. Further, without the theory it is impossible for me to utilize this information in the context of my practice as a fitness professional, I understand that fascia can restrict, I have a theory to work with, and it influences my practice. So far, my only logical conclusion to a statement - "fascia contracts" is "How, and So What?

Eric Beard, June 22, 2010 at 4:51pm: I remember when I first heard some researchers found motor units in fascial tissue and in my mind further blurred the delineation between muscle and fascial tissue. I also wondered if it was in just some odd genetic adaptation in a few individuals. I am looking forward to learning more about fascia as more research is produced. I love this DVD…great view of fascia as a living organism. Worth the $60!


Eric Beard, June 22, 2010 at 4:54pm: RC, great summary of the gamma loop and associated fiber function. This can be daunting to wrap our heads around:)

Derrick Price, June 22, 2010 at 5:36pm: BB, I'm not sure what you mean that there is no sound theory to back up this claim? RC gave you the theory that fascia has contractile properties and this claim has scientific evidence to support it. We discussed this a couple weeks ago, here's an excerpt:

"This is also where the conscious vs. subconscious notion comes into play. Consciously, muscles are 'activated' they are in essence 'actuators'. However, sub-consciously muscles react - they are reactors to the forces placed through them via gravity, GRF, momentum, etc… they respond to lengthening (muscle spindle - stretch reflex) or what we call 'loading' - this idea has some support in recent research here is an excerpt without getting lengthy:

"The classic view of skeletal muscle is that force is generated within its muscle fibers and then directly transmitted in-series, usually via tendon, onto the skeleton. In contrast, recent results suggest that muscles are mechanically connected to surrounding structures and cannot be considered as independent actuators. This article will review experiments on mechanical interactions between muscles mediated by such epimuscular myofascial force transmission in physiological and pathological muscle conditions. In a reduced preparation, involving supraphysiological muscle conditions, it is shown that connective tissues surrounding muscles are capable of transmitting substantial force."

This fully supports the idea/theory of Tensegrity (Functional Biomechanics), a principle of movement that discusses how the body is always looking to disperse/distribute force/tension throughout the entire system to optimize energy expenditure and stability during a movement. (PTA Global Tensegrity Lecture). If we looked at the body solely as mechanical, independent structures, we would have to wonder why we are not constantly crushing our joints, tearing our muscles and be completely exhausted after performing any movement (hmm sounds like a traditional body builder?).

There is plenty of science, theories and practical application awaiting for you in the PTA Global curriculum.

EB and everyone, here's another book that I think you would enjoy!


Rodney Corn, June 22, 2010 at 6:21pm: Brent… you make excellent points! You ask great questions and you are loyal to your education… I always have to keep in mind that I know essentially nothing - especially about this magnificent body we have been given and how it works. It is capable of far more then we know and is able to respond to far more than we think possible. There are many philosophies of how to train it, treat it, and make it 'better'. Most of them work fantastically and I have seen/experienced many of them personally. So if we agree that there are many ways to get the body to do something, than the rest of this is just gymnastics and in my ignorant opinion, it all boils down to 1) what is the 'trainer' capable, competent and comfortable with and 2) what will work best for the client, their personality, preference, abilities and issues. If it doesn't meet the client where they need to be met, it runs a high risk of adding stress to the system and producing non-compliance. Either one makes for a bad day ;-)

That being said, I have seen and used a technique whereby you 'load' muscles in 'other' planes and this 'releases' them or up-regulates them thus allowing better function of the whole - capsule, joint, tissue, motion. This is the premise behind Mobilizes. And they do work most of the time. Does this mean it is the only way or the best way - NOPE! It is just another way. Sometimes tissue gets 'stuck' in 1 plane but by moving it in another plane you 'unstick it'. Sorry I am not using clinical words here - just sounds more visual when I use a simple term.

I understand your view of 'long' and 'short' and 'muscle balance' in dyskenisis - ( can I just say "jacked-up joint" instead..?) but again it all becomes relevant to your philosophy. For example, in a "lower cross' syndrome (or whatever term you choose to use) you would say that the person has a 'long' biceps femoris right?

But if their foot is turned out, is the BF really 'long'? What if the foot is not turned out, but the tib/fib is externally rotated ('supinated')? What if the fibula is posterior translated on the tibia? What if the pelvis is rotated transversely? A lot of variables to check to ensure that what the protocol says is happening, is actually happening. SO while long and short may be good starting points - we need to define them relative to 3D motion to make sure we address the body as it operates.

As far as your impingement scenario - you would have to identify the cause of impingement… what if the psoas' inability to shorten was the cause of the impingement and when you 'activated' it in a shortened position, the impingement went away (BTW - this is exactly what happened to me last weekend - had impingement in L hip and strengthened my psoas and impingement immediately went away right in front of 15 people, Derrick Price was there as well - cool huh?)…

Lastly, I have 2 options here with the research deal again:

1- I give you some research (I thought I actually gave you a few references in another post) OR

2- As any good teacher would do, I ask you to go beyond your text books and actually look up research - you can use Pub Med or talk with the NASM research team. I am quite sure that they stay up to speed on the latest info out there and its application to training and the industry.

Let me know what you would like to do BB and thanks for your brilliance and contribution to the industry. Keep it up ;-)

Rick Richey, June 22, 2010 at 7:36pm: There is a lot of good debate going on! We have gone from a question about hip weakness and activation, into a the importance of fascia on weakness and activation, intra and extra fusial fibers, then to be brought back to the hip with an example of Rodney adding strength to the psoas to release an impingement.

So, back to the hip. Think about the TFL. If I am adducted, Internally Rotated, and Flexed at my hip is my TFL shortened or lengthened? It is short leading to flexion and internal rotation, but it is not abducted. If it did get tighter would it suddenly abduct my hip as well, or would it flex and IR more? This is the problem when you just look at 1 muscle, and not its synergistic function. A similar point would be Rodney's point about the biceps fem. Is it lengthened in an ant. pelvic tilt IF the tib/fib is externally rotated? The same point should be brought up about the importance of gastroc extensibility in a squat! If the knee flexes more than 90 degrees in a particular squat and the ankle can only get to 5 degrees of dorsiflexion whether if the knee is flexed or extended we should check ourselves on the contribution of gastroc tightness.

Now, as far as fascia is concerned, we a about 150 years behind on research. Researchers are just now finding myofibrils, collagen strands as mitochondrial tracks, and new layers. These are things that could have been seen a century ago if researchers then didn't just throw the fascia to the side to get to the good stuff! There is no doubt that there will be more and more found about the use and function of fascia, but i HAVE to agree with Brent that the function of muscle is obviously to contract. SO, the fact that fascia does have contractile properties is important, but incredibly nominal compared to muscle!

I have more to address, but my daughter wants to go outside. Before I go I want to say that Brent, I know you love your books, but you really should stay up to date on research! LOL! :-)

Rodney Corn, June 22, 2010 at 7:53pm: ‎… thanks Rick - well said!

Guys, at the end of the day, after everyone has patted themselves on the back, it doesn't matter if it is muscle or fascia…! What matters is did the client get what they 1) Wanted and 2) Needed.

Not sure why cannot love both fascia AND muscle - they love each other… it isn't about who's right, it about what's right. Muscle and fascia go together, each has unique properties, but they are a team. We as 'educators' need to take a lesson from this wonderful body we have been given and be a team that embraces the 'other' philosophies, especially when we do not know much about them. We do not need to use them if we chose not to, but at least learn about them.

One such philosophy is MAT… Greg Roskopf is a brilliant, humble and extremely practical clinician. His MAT technique is very powerful and works very well! It is not 'functional' by industry standards and it does not utilize any form of 'stretching' technique, BUT it works. I know because I have had it done to me and have spent hours talking with Greg about it…

My last comment is this… get to know what else is out there and look at it through a different set of goggles. Take off your bias and your comfort and I assure you, you will be amazed at what you find. ;-)

Great stuff peoples - let 'er roll…

Brent Brookbush, June 23, 2010 at 12:02am: Great discussion kats…. These discussions just keep getting deeper, and deeper… I am absolutely humbled by the amount of knowledge that was brought to this discussion.

I think in a future post we should address a topic that rarely is discussed in a formal manner. How does a trainer, as well as, the professionals on this panel, assimilate, critique, and discern the great info from the less than great info available to us. Rodney mentioned bias in one of his earlier posts… This is one of the weaknesses in our industry. The marketing of products and ideas often thwarts high level educated conversation. Although all information has some source or level of bias… How do we keep it to a minimum.? One of my goals for these discussions was to have it out with industry professionals about various topics… in essence to pit our biases against each other to get to the heart of each topic. This would be similar to several researchers doing the same study to compare results. I would love to start some discussions off line to talk about how we could approach this topic… less bias, quality information, and scientific rationale.

My apologies to Rodney for not reading the information you posted for me, and not being clear in the rationale I was looking for… It was absent mindedness and nothing more I assure you. I look forward to reading the article, and increasing my understanding of connective tissue physiology.

Thanks to Eric Beard for mentioning the motor units found in fascia, this does make the argument for fascia mush stronger.

Thanks to DP for his posts… you definitely set this discussion in motion.

Thanks to Rick for bringing a little love to our discussion - because all the world needs know is……

Once again, thank you to everyone… you cats are the best in the business and it shows with every post.

Derrick Price, June 23, 2010 at 12:55am: Cheers brother, you are the man!! Thank you for getting these discussions going as I learn so much from these interactions from some of the best in the biz.

Brent Brookbush, June 23, 2010 at 10:32am Tell me about it, I am afraid with all the knowledge that’s being shoveled in, if my brain grows any faster I am going to have stretch marks on my forehead.

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