Meditations on Mobility

Reading time: 10-15 minutes

Key points:

  • Mobility and Flexibility are two different things
  • More mobility is not always better. You need just enough, but no more.
  • Mobility can be used to “un-glue” tight structures (Postural Deficits)
  • There is no “normal” when it comes to posture.
  • There are a multitude of techniques (modalities) commonly in use to improve mobility.
  • There are two types of improvements: Immediate changes, and changes over time.
  • Different structures in the body change at different rates.

Mobility is an often confusing subject in the realm of fitness, health, and therapy, with well established experts in the field literally at each others throats in disagreement. Here are a few of my thoughts on the subject, based on my experience and contemplation.

Mobility and Flexibility: A Definition

I define mobility as an individual’s ability to painlessly and effortlessly assume a certain position without external load. Mobility is different from the term flexibility as it implies an active range. We must also differentiate between local mobility (such as in a particular joint) and global mobility (the ability to assume a position or bodily shape).

One’s flexibility is the passive extensibility of tissues. If you were to stand with your back against a wall and I grabbed your leg and lifted it as high as I could while you simply relaxed, this would represent your flexibility. Now, if I asked you to actively raise your own leg, this would represent your mobility.

It is perfectly possible, and indeed common in certain populations to have a mobility to flexibility discrepancy. Some people have a great deal more flexibility than mobility. This is usually seen in female dancers, yogis, and others we term hypermobile. Generally this is undesirable as this difference in range represents the zone in which the individual cannot control  their range of motion (ROM). For optimum performance and resilience to injury, we want the difference to be as small as possible. There are rarely situations where we want to be able to bend more than we can actively control.

How much is enough?

It is generally believed that since mobility is a good thing, the more you have of it, the better. Although most people need to improve their mobility, the particular needs of an individual vary greatly. Does a basketball player need to be as flexible as a gymnast? No, and in actuality, increasing the basketball player’s mobility beyond what he needs in a game situation may actually inhibit performance and increase risk of injury. Mobility is all about positions. You need to identify what positions you need to spend time in and make sure you can attain those positions effortlessly, without load or speed. In the case of the basketball player, they rarely have to bend their knees and hips lower than parallel. Gymnasts, on the other hand, regularly explode into full side splits in mid air. It behooves them to be able to do side splits in a slow, controlled manner before throwing themselves into it with speed.

Is this necessary for a basketball player?

Is this necessary for a basketball player?

But what if you are not a professional gymnast or basketball player. How much mobility do you need?  Again, to provide an adequate answer to that question requires individualizing the approach and assessing each person separately. Different people have different mobility needs as well as genetically determined anatomical limits to mobility, such as the length of bones, which don’t bend very well. However, a general rule of thumb is that you must have the requisite mobility present in a movement or joint before you apply load to that joint. For example, let us say that you wish to perform the overhead squat exercise, but you have very hypomobile (tight) hips, shoulders, and ankles. The result would be one of two things. Either, the stiffness of the shoulders would prevent you from holding the weight overhead during the squat and you would drop the weight, which could prove dangerous. Or, you would use the weight to squeeze yourself into a position you normally can’t get into, but for the added weight. This would result in the load being transferred to non-contractile structures such as your joints, ligaments, and spinal discs, which would most definitely prove dangerous. Just because you can “fake” a movement does not mean you should be doing it.

Restoring Postural Deficits

But what about posture? Don’t we need to stretch to improve our posture? Well, sort of. The answer is not straightforward here. Research and clinical experience has rendered the antiquated view of posture and muscoskeletal health somewhat obsolete. The fact is, it has been shown time and time again that posture is not linked to pain. Also, what is “good posture” anyway?  I study posture and movement on a daily basis and can tell you that there are many shapes and sizes out there. Some have pain, some don’t. Your posture is a combination of your anatomy (which is determined by genetics and activity over a lifetime) and  your current neurological muscle tension pattern. Your dynamic posture is in large part a choice made by your nervous system based on what it feels it needs to do in order to guard the system and maintain baseline functioning. When you “stretch” a muscle you are not actually mechanically lengthening it, you are stimulating it to relax. This is a somewhat complex topic and I will delve more into this later.

What does appear to consistently cause pain is tissue stagnancy. That is, holding static positions for prolonged periods with your body in a mechanically compromised position, such as sitting at a desk in front of a computer. If you are a relatively sedentary person and work at a desk there’s a good chance you “tighten up” in certain areas. The hips and shoulders are areas both commonly compromised by long-term sitting. Statically holding muscles like the hip flexors or pectorals in a shortened position lead to these muscles becoming rigid, painful and less mobile. Trigger points (commonly known as “muscle knots”) form in these muscles which may lead to referred pain patterns. You have most likely experienced this at one point or another. Someone presses into a muscle in your shoulder and pain shoots up and out in all directions and often manifests in strange places, like behind the ear or the back of the eye. This is muscle pain, not nerve pain. Nerve pain almost always goes downward or outward. Aside from direct muscle pain, these areas also affect neighboring zones. When the pecs shorten, they pull the neck forward. When the hip flexors shorten, they apply an extension load to the low back. All of these things work to tweak the body into positions where stress concentrations form in joints that are at a leverage disadvantage. After a certain threshold point, your brain has had enough and starts to press the pain button. I call this postural-deficit related pain. Pain is occurring due to an unnatural deviation from the individual’s normal state. Restoring these postural deficits using mobility training is necessary and useful.

A Note on Normality

I should note that I do not like the word “normal” in this sense. Trying to move something back to normal not only implies that something was “abnormal” to begin with, but that we somehow know what normal is. Yes we have a general idea of what a good posture looks like and what a crappy posture looks like, but this concept is an insidious one. It comes from the normalization camp of therapy, whereby every intervention is an attempt to bring the individual back to normal. Yes, we have guidelines on how your scapulae are supposed to align, what your spinal curves should look like, how your knees align etc, but these are just that, guidelines. A more refined way to view this is through the adaptation and load management paradigm. Human biology is remarkably flexible. There are people out there missing limbs, with spines bent sideways, with partial paralysis. Many of them living mostly pain-free. If the causes of pain were simply due to structural “abnormalities” you would see much more pain in this group, and much less pain in those with more “normal” postures. This is clearly not the case. These individuals adapt, and their structure becomes normal. Remember, pain is merely a signal from the brain that it perceives some threat or damage occurring in the body. Stress concentrations in certain joints due to either light force over a prolonged period of time (such as slouching for hours or wearing bad shoes) or excessively high force for a short period of time (such as a fracture or strain) will both cause pain. This is a problem of load management, namely inappropriate amounts of load in one place. The solution is to disperse the load, either through removing tension in key spots of the body, or by retraining movement patterns to shift load from these stressed areas. Shifting stress concentrations removes the need for a pain signal.

Note: Although I dip into the science of pain here, it is such a massive topic that I am going to dedicate another article to pain science in the future. 

What exactly is mobility training?

Having established a working definition of the word mobility, we must also understand the word training. To train for something implies that you have a fixed and quantifiable goal you are working toward. Your efforts are in an attempt to get you from A to B. Doing this requires knowing what the goal is, as well as the right tool to get the job done. Although I love stretching, yoga, and other recreational flexibility pursuits, my problem with them is that they mostly have no clear goal. Getting “more flexible” doesn’t mean anything. It doesn’t solve movement problems, and can in some cases be detrimental. However, if I tell you that person X needs to improve their shoulder mobility so they can reach overhead during swimming without compensating in the low back and neck, then that would be actionable information. You would improve the individual’s shoulder mobility to the degree that allows them to be able to perform the function of swimming optimally.

Once you have decided what your mobility needs are and what deficits you need to correct, like normal exercise, you program it. Solving these mobility deficits requires different tools and techniques. The most common (and uncommon) methods  are as follows:

  • Self-Myofascial Release: Self massage using various implements. Thought to address contractile dysfunctions in muscle such as trigger points.
  • Stretching: Lengthening of a muscle using various techniques. Can be useful for restoring resting length following periods of positional shortening, such as sitting.
  • Joint Mobilisations: Various methods that glide, slide, pull, and wiggle joints to create better motion, known as arthrokinematics.
  • Resistance Training: It should be noted that correctly performed resistance training (i.e. strength training) will improve mobility. Performing weight lifting with a large range of motion under control can often improve mobility the most, particularly in large, very strong muscles, and also  improves strength.
  • Breathing and Visualizations: Controlling the breath and mental state is a known way to access the parasympathetic nervous system, which can reduce global tension in the body.
  • Shaking or “self-vibration”:  Vibrating movements, or using technology like power plates can be used to release muscular tension.
  • Activation of Stabilizers: When joint stabilizers are responsive, the joint is held in the center of the rotational axis, and thus moves better.
  • Positional Release: Placing the body into certain positions to allow the muscles to relax, or to allow certain body parts to disassociate from others, such as the hips to low back.
  • Movement: Sometimes correcting mobility dysfunction is about simply moving better. If you can correct mobility issues through improved motor control and better positioning through movement, it saves you a lot of time.

Note: This is by no means an exhaustive list, and I could go on. However these are some of the most common modalities out there. Also, the description of each is rather limited. Going through each modality in detail could take several books, and is beyond the scope of this post. 

To give you an idea of what these may look like, check out these two mobility montages I made a while back, when I was sporting some crazy cave-man hair!

“Instant” Release and Adaptation over time.

I divide the response to mobilizing as the immediate effects versus the long-term effects. If you stretch or foam roll a muscle and you increase the range of motion (ROM) of the joint then what you have really done is tapped into the neurological tension release pathway. There is no actual mechanical lengthening of muscle going on, or deformation of the muscle belly. The pressure or stretching of mechanoreceptors in the muscle indirectly cause the brain to downregulate the amount of resting tension in the muscle.  These effects should be somewhat immediate, visible within 2-10 minutes of mobilizing. Use this to dynamically warm up the body and restore postural deficits. Beyond this, if you cannot move into a certain direction due to restrictions in bony anatomy, no amount of foam rolling will change that.

However, long-term change in body structure appears to be possible. Wolff’s law states that bone remodels as a result of the stress imposed upon it over time. This happens through a miraculous process called mechanotransduction, where mechanical stimuli are converted to biochemical signals on a cellular level. The implications of this are that with increased muscular force being exerted on bone, the bone itself becomes denser. Also, the bone can sometimes re-shape. This can most prominently be seen in the negative ways bone can remodel due to poorly aligned stress, such as heel spurs from a collapsing ankle, bunions from out-turned feet, etc. Conversely, too little stimulus and bone starts to weaken and become brittle. Medically, this is called osteoporosis, and can be treated through diet and resistance training. Davis’ law states much the same for soft tissues of the body and specifically refers to fascia, tendons, and ligaments. These structures remodel and strengthen based on the stimulus they are exposed to.

The mobility interventions we do in the gym or on our living room floor are what give this “immediate release” effect that is driven by the nervous system. This prepares us for exercise or sport, and also removes pain by restoring postural deficits or changing tension patterns (and thus relocates areas of excess loading). The long-term changes in bony and soft-tissue structure are driven by how we move, what type of exercise we perform, and the positions we assume in everyday life. Our bones mold like coral and our tendons like rubber, slowly but surely as a result of internal forces (muscle contractions) and external forces (gravity and how we position ourselves relative to it, i.e. sitting). Almost all the tissue in the body adapt, they simply do it at different rates depending on their plasticity (ability to change).

Summary

This post is by no means complete, and there is still much that is not understood about mobility in the world of health and fitness. Following new discoveries and changes in research I suspect I will have to revise different aspects of this. In Part two of this series I will detail the process of mobilizing, how to assess your mobility needs and how to resolve it in the best way.

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