DIFFERENCE BETWEEN MOBILITY AND FLEXIBILITY

There is a widespread notion that everybody should stretch and that more range of motion (ROM) is always better. You may have seen people from both sides of this spectrum – yoga masters who can put their legs behind their head and older, sedentary individuals who cannot bend down to pick up shoes from the floor. ​

Even though everybody should be able to demonstrate good ROM in all of their joints, there is a limit to this where excessive ROM will cause joint deterioration and inability to properly stabilize joints. Before we move on to explain what is the optimal ROM and how you can move better, I want to point out the difference between mobility and flexibility.

Mobility and flexibility are intimately related, however, they are two distinct characteristics. Flexibility is defined as the ability to passively achieve ROM, whereas mobility is defined as the ability to actively control ROM. For example, a good flexibility test would be to have someone pull or press on your body to achieve end ranges of motion (e.g. passive stretching).  Conversely, good mobility tests would be any movements that do not include external assistance (e.g. something pulling or pushing on your body), but challenges your body to control and stabilize that movement while trying to achieve end ranges of motion (e.g. full-depth squat, forward and side lunge, picking stuff from the ground, etc. ). So it becomes clear that for performance and everyday tasks, we need mobility, aka ROM that we can actively use and control.

To be able to perform full-depth squat for example, you need to have good passive ROM (i.e. flexibility), but in addition to that, you want to have strength and control over that ROM. In other words, mobility is based on flexibility and strength:

MOBILITY = FLEXIBILITY + MUSCLE STRENGTH

​From this equation, it becomes clear who should be doing more stretching (i.e. flexibility) work and who should be doing more strength to have a better mobility. Let’s refer to our previous example:

    1. Yoga masters – most of them should not be doing any stretching at all, but focus on strength to be able to protect ligaments and have adequate joint control in case they need to run, jump or change movement directions abruptly.

   2. Older, sedentary individuals – even though they might have strength to control their restricted ROM, they do not have enough ROM to perform movement tasks at hand. So they should be doing more flexibility work, but at the same time, not forgetting about strength work.

So what is an optimal range of motion for you? After performing our assessments, we reference the American Academy of Orthopaedic Surgeons manual to determine in what direction we need to go. They have developed a list of every major joint in the human body and their average ROM. In the case of an excessive ROM somewhere in your body, we do not employ any type of stretching for that body part. In the case of a reduced motion somewhere, we focus our efforts on that specific body part to regain normal physiological range of motion.
 
In order to move better and perform at your best, you need to have adequate ROM, but at the same time you need to have muscle strength to be able to control that ROM. Having good mobility protects your joints, increases performance and makes you feel better knowing that you can express yourself through movement in a safe and efficient way.

Takeaway message – large ROM without control is useless and potentially dangerous. Short range ROM with adequate strength is equally dangerous. Optimal strength and range of motion is a way to go.