Are You Mobile or Are You Flexible?

A minimum range of motion is required at all joints to maximize your movement efficiency, but when you're working to improve your splits are you working on mobility or flexibility?  Are your tight hamstrings a sign of immobility or inflexibility?  Is "tightness" ever a good thing?  Mobility and flexibility are often used interchangeably but they are quite different.  Let's define the two...

Flexibility: Total range of motion at a joint. 

Mobility: Functional control at end range.

You see, flexibility simply refers to your ability to get from point A to point B.  Mobility refers to your ability to control the movement and do work in that range. Improved mobility translates into improved movement.  With improved movement we improve athletic performance.  Imagine for a second if a gymnast could get into the splits on the floor with no problem, but when in the air the same athlete couldn't get his legs nearly horizontal.  This demonstrates flexibility but not mobility and translates into a sub par athlete. (Side note: isn't "sub par" a good thing?  That has never made sense to me.)  

Some joints are meant to be mobile while inherently others are meant to be stabile.  Gray Cook's joint-by-joint approach describes the alternating pattern in which mobility and stability play a role in the human body but to keep this blog a blog and not a book I will simply say that if you aren't moving where you should be moving, you will move where you shouldn't.  For example, If my ankle doesn't have enough mobility for me to squat properly I still may be able to squat I will just get the motion from somewhere else.  My foot over pronates, my knees may fall into valgus and my femur internally rotates.  My movement is severely compromised and I am set up beautifully for serious injury.  You MUST have proper mobility where we need it in order to prevent funky movement like what was just described.  I recently saw a baseball player with a very similar situation.  His ankles lack essential mobility and the whole system has fallen apart.  As a result his achilles tendons are extremely bowed inwards setting him up for possible rupture.  Career ending?  For sure.  So let's address his ankle mobility and lock it in with proper movement and exercise effectively re-teaching him how to move and reducing risk for serious injury while also improving his performance.  


How to improve your mobility?

Musculoskeletal work:

I like to start with the simple things and take them off the table.  We can quickly and easily improve mobility in an immobile joint with different soft tissue modalities.  These methods help break adhesions and unstick layers of your fascia and muscle.  Mulligan mobilizations, active muscle pumping, Active Release Technique, joint manipulation and Graston are a few that our team uses at EP.  Before you workout you will often be prescribed specific banded mobility work in which you will improve your positioning and mobility with banded stretching and exercises.  At the conclusion of each workout we continue to stress mobility work with self myofascial release using tools like foam rolls, tiger tails, tennis balls and lacrosse balls.  

Nervous system adaptation:

Here's the catch, the soft tissue work, foam rolling, joint manipulation, and the corrective exercises we prescribe often use much less force than what is required to change the physical composition of the tissue.  So if many times we aren't changing the tissue but we are gaining range of motion what is happening?  We may be simply proving to the nervous system that we have an increased range of motion and that we are ok being there.  Todd Hargrove, author of "A Guide to Better Movement,"  describes the nervous system as an "overprotective mother."  Its entire purpose is to keep us safe and alive.  Throughout the evolutionary process a groin strain very well could have meant immobility and death.  To avoid that scenario the nervous system throws the brakes on when you begin to hyper extend or abduct the leg.  Why risk it?  You have to prove to the nervous system that it is safe and you can control the range of motion.  Our manual work and corrective exercises may be just that proof it is looking for.  We are proving to ourselves that we can get there and control it.  

We can loose the "over protective mother's" trust quickly as well.  A person forcing themselves into the splits, pushing past immense pain and the agonist muscle contractions, may be actually doing just the opposite.  In response the nervous system tightens up even further.  It really throws the brakes on and instead of improved range of motion we now have huge inhibition.

Could "tight" muscles be beneficial?

Another point that we don't want to ignore is more range of motion is not always ideal.  Think about a sprinter with "tight" hamstrings.  Assuming a minimum range of motion is already achieved the high level sprinters will use the springs of the hamstrings to explode into movement.  Muscles have an ideal length at which the most cross bridges are in contact with each other and ready to go.  At this length the muscle can contract with optimal efficiency and force.  When the muscle is stretched slightly it creates even more force before contracting again.  Imagine you are attempting to jump as high as you can.  You bend down and explode from the squat position correct?  You would not get nearly as high if you were asked to bend down and pause at the squat position before exploding.  In the paused scenario you are not taking advantage of the stretch and "spring" of the passive structures of the muscle or its eccentric strength properties.  But shhhh, don't give away Usain's secrets.


  1. Hargrove, Todd.  A Guide to Better Movement: The Science and Practice of Moving With More Skill and Less Pain.

(Chiro and PT friends, if you haven't read this book yet please buy it right now.  I promise it is an invaluable resource.)