Home Blog 3 Principles for Understanding and Improving Mobility

3 Principles for Understanding and Improving Mobility

Written on June 30, 2016 at 4:16 am, by Eric Cressey

Today's guest post comes from Dean Somerset, the creator of the excellent resource, Ruthless Mobility, which is on sale for 60% off through the end of the day on Monday, July 4. Dean is a tremendous innovator and one of the brighter minds in the fitness industry today, and this article is a perfect example of his abilities. Enjoy! - EC


Mobility can be described in a number of different ways, depending on who is writing the story: yoga, flexibility, stretching, movement training, dynamic warm-ups, bendy stuff, and in some cases “how the heck do you even do that?” Regardless of what it’s called or who’s doing it, there are some basic rules and physiologic elements to be aware of when it comes to understanding mobility and how to use it in training programs. Today I wanted to outline the "three big rocks" of developing, using, and maximizing mobility in a safe and progressive manner. 

1. Structure Determines Function.

It’s easy to say that genetics are a separating feature for those who can gain a lot of muscle and those who have trouble adding a pound. The same can be said of those who are congenitally lax (via something like a higher Beighton hypermobility score or a diagnosis of Ehlers Danlos syndrome), compared to people who move like the tin man. Some of this could be connective tissue related difference in collagen to elastin ratio, but much of it could also be considered by the shape and orientation of the joints themselves.

In terms of the acetabular angle, D’Lima et al (2011) found in a computerized prediction model for prosthesis implantation that:

a. those with more acetabular anteversion (forward placement on the pelvis) had greater flexion range of motion and less extension
b. lateral placement of 45-55 degrees gave the best overall mobility
c. a lateral angle of less than 45 degrees gave more flexion range of motion and more than 45 degrees gave less rotation capability
d. if the femoral neck was thicken by 2 mm in diameter, it significantly reduced the range of motion in all directions, irrespective of placement.

Higgins et al (2014) even showed there was a large difference in anteversion angles bilaterally in the same individual (potentially lending some validity to PRI concepts of inherent asymmetry), with as much as a 25 degree difference in anteversion angle between left and right hip. This could translate to a difference in flexion range of motion of 25 degrees between your two hips, without any other feature affecting the outcomes. Zalawadia et al (2010) showed there’s a big variance in the femoral anteversion angle (whether the head of the femur pointed more forward or possibly backward) as the femoral neck attaches to the acetabulum, with the majority being between 10-20 degrees.

Additionally, some acetabulums have too large of a center edge angle, where the socket faces more inferiorly than laterally, which makes impingement during abduction more likely compared to a smaller center edge angle.

Screen Shot 2016-06-29 at 9.32.28 PM

These structural differences are primarily set and unchanging after puberty when bones don’t deform as easily to external forces as with young kids. Baseball pitchers can undergo deformational changes at the proximal humerus (upper arm) to allow a much greater external rotation range on their throwing arm compared to adults who pick up the sport later in life. Eric showed that with his comparison of presidential first pitches HERE.

With advancing age, joint range of motions tend to reduce further with degenerative changes to the structures involved, either with an increase in concentration of cortical bone at contact areas, a reduction of cartilage thickness, or decreased fluid content of the joint space itself. The end result is a tighter joint that doesn’t move as easily.

Most of these types of changes, barring injury or disease, tend to not be limiting factors in mobility until many decades have passed, so if you’re in your 20s and concerned about your lack of mobility, it’s pretty safe to say that it’s likely not related to degenerative changes just yet. If you’re 50 or 60, it’s much more of a likely scenario.

This Canadian study showed that men lost an average of 5 degrees of shoulder abduction and 6 degrees of hip flexion per decade between 55 and 86 years old, while women lost an average of 6 degrees of shoulder abduction and 7 degrees of hip flexion in the same age range, and that this loss sped up after 70 years old and was actually not linked to self-reported activity levels. Being more active is better for everything as you age, but based on this study, not necessarily for keeping your mobility into your golden years.

What this means is that everyone will be different in terms of how much mobility they have and in which directions or movements. One person may be able to press overhead because they have joints that easily allow it, while another may never get there due to specific limitations, and a third may just not be ready to press yet. They may have the specific ability to do the motion, but don’t have the control or strength at the moment to do it effectively, which is where part 2 comes in.

So how do you determine a structural limitation? The best mechanisms are simply to see what the range of motion looks like in a couple of scenarios:

a. passive – have someone move you through the range while you’re relaxed)

b. supported - pull the joint through a range without using the muscles involved in the action. (Think a hamstring stretch with a towel wrapped around the foot and pulling on it with your arms)

c. in a different position or direction – in looking at hip flexion, compare a squat to a rock-back or Thomas test to look at the same range of motion.

If you consistently get the same joint angles in different motions or positions, it’s reasonable to believe that could be the true limit of your flexibility based on structural aptitudes. There’s always a potential that the limitation could be something else, and if you involve some of the training practices and options used later and notice an improvement, it’s a happy bonus. Short of developing X-ray vision, these are some of the best options for determining structure that everyone has available to them, whether we’re talking about the clinician, trainer or average meathead looking to get all bendy and stuff.

2. Can you actually get there?

Now, let's consider shoulder mobility; imagine that we look at an individual in supine and there’s no limitation standing in the way of going through full shoulder flexion.


However, when this same individual is asked to bring their arms overhead in an upright position, they do some wonky shoulder shrug, low back arch, and their upper lip curls for some reason. In short, they aren’t able to access that flexion movement very well, even though they have the theoretical aptitude to get there on their own.

We’re looking for the image on the right, but wind up getting the image on the left:


Now the great thing about the body is it will usually find a way to get the job done, even if it means making illegal substitutions for range of motion from different joints. In this case, the lack of shoulder motion is made up with motion from the scapula into elevation instead of rotation, and lumbar extension in place of the glenohumeral motion.

This by itself isn’t a problem, but rather a solution. It’s not bad to have something like this happen by itself, but it does alter the specific benefits of an exercise when the segments you’re looking to have do the work aren’t actually contributing, and you’re getting the work from somewhere else. There’s also the risk of injury from poor mechanical loading and improper positioning that increases the relative strain on some areas that aren’t meant to be prime movers for the specific exercises.

Now, the big question is whether someone is willing to not do an exercise because they’re demonstrating that they’re not ready for at the moment. If a client wants to squat in a powerlifting competition, but his hip range of motion makes it very difficult to get below parallel to earn white lights without losing lumbar positioning or grinding the hip joints to pieces, how willing would he be to adjust his training or eliminate that possibility to save a lot of hassles? Some people identify themselves by their sport, so telling them not to do what they love isn’t an option. I’ve worked with a lot of runners, and saying “don’t run” tends to go in one ear and out the other.

Back to the overhead example, maybe going right overhead isn’t possible at the moment, but a high incline press can be done easily. This is working in what Mike Reinold calls on Functional Stability Training: Optimizing Movement “Green Zone vs Red Zone training.” Overhead at the moment is a red zone movement as they can’t get there easily and on their own. Green zone would be a landmine press, where they’re still working on flexion, but not moving into a range they can’t easily access.

One manner that could help an individual access this range of motion if they have shown an ability to get there passively is through what Dr. Andreo Spina calls eccentric neural grooving of the motion. Use either a support or pulley to get into the terminal range of motion, release the support or pulley and try to maintain the terminal position while slowly moving out of the end range as controlled as possible. Here’s Dr. Spina doing ENG work on the ankle and anterior shin for some dorsiflexion work.

Here’s another version with yours truly working on a similar variation via controlled hip abduction:

You could do this for the shoulder easily enough as well by grabbing a rope, pulling the shoulder into flexion, releasing the rope, and trying to maintain the position before slowly lowering the arm out of terminal flexion. Just make sure you’re not letting your low back arch or shrug up your shoulder blades in to your neck.

3. Can you use it with force when needed?

So now you’ve shown you have the joints to do stuff, you can get there on your own without assistance, and you want to train the heck out of it to look like your favorite Instagram bendy people.

One thing to consider when exploring these ranges of motion is that force production tends to be greatest in mid-range positions, likely due to the greatest torque development required to overcome natural leverage elements and also due to spending less time in the end ranges. There’s also the reduction of cross bridge linkages in these positions, limiting sarcomeric action when you’re gunning your biceps in peak flex.

Controlling these end ranges (even if the goal may not be to develop maximal force in them for moving the biggest weight from point A to B) can help expand the usable range of motion where peak torque development occurs, as well as provide the potential for expanding sub-maximal torque percentage ranges of motion. These movements aren’t easy and tend to take a lot of mental energy coupled with physical effort, but if getting awesome was easy, everyone would already be there.


To round things out, understanding and developing mobility comes down to:

a) having the structure to produce the range of motion
b) being able to get into position to effectively use that range of motion
c) building strength and conditioning within that range of motion to keep the ability to use those ranges for a long time, and through as many positions and directions of movement as possible.

Some specific movements or positions may not be possible due to your own unique structure and abilities, but work hard at using everything you do have, build strength throughout the entire range of motion, and enjoy the process as much as the outcomes.

Note from EC: If you're looking for more mobility tips and tricks - and the rationale for their inclusion in a program - I'd encourage you to check out Dean's fantastic resource, Ruthless Mobility. Your purchase includes lifetime updates and continuing education credits. Perhaps best of all, it's on sale for 60% off through this Monday (7/4) at midnight.



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