What is the difference between Flexibility and Mobility?

Flexibility is 2008, while Mobility is the thing nowadays. If this is your answer when asked about the difference between Flexibility and Mobility, you are at least more knowledgeable than people who think the words are synonym - because there are clearly NOT. Let’s have a look at the many differences and the link between them.

Flexibility - a definition

There is no scientific nor official definition of flexibility in the anatomic context. We can refer to the following:

“Flexibility refers to a connective tissues (muscles, ligaments, tendons) ability to temporality elongate.” (s. https://barbend.com/mobility-vs-flexibility/)

This definition indicates that flexibility is a matter of soft tissues and their potential to lengthen. It does not hint the other important fact about flexibility: The elongation is caused by outside force from a tool and/or other person.

Mobility - a definition

Also, anatomic mobility is not officially defined. There are however several attempts of professionals to describe mobility:

“Mobility is our ability to take our body through a range of motion, before being restricted, with control.” (s. https://barbend.com/mobility-vs-flexibility/)

This definition shows that mobility is broader than flexibility; It does not only measure the potential length a muscle can achieve, but describes the full motion range of joints with all their insides and connective parts.

We want to add that - not shown in this citation - mobility is active while flexibility is passive. Mobility is the movement of a joint or chain of joints from their internal forces. No outside impact (e.g. pushing from a training partner, bands etc.) required.

Flexibility is a part of Mobility

So it is actually inaccurate to ask for the difference between both terms, but more about the relation - flexibility is a part of mobility, but not the other way around.

A joint can only move through its full range of motion if the surrounding soft tissues are flexible. A common example: When your calve muscles of Achilles tendon is tight, your ankle (joint) mobility will be limited.

The other way around, you can be flexible in a body part but not mobile. Mobility requires flexility, but not the other way around (it’s like a very one-sited, depending relationship).

A huge difference: Mobility requires strength

Flexility is something very passive. Mobility in contrast requires control and strength. This is a main difference.

We all know these people who can squat Ass to Grass in an airsquat, but barely make it to parallel with some weight on their back. Without strength and body awareness, the best flexibility will not get you mobile.

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Being flexible AND mobile: Why it matters

CrossFit contains many movements which require great mobility, especially kipping gymnastics (Butterfly Pull ups etc.), squatting and Olympic Weightlifting.

As we know by now, flexibility is a part of mobility, so you have to work on it in order to become more mobile. Another important fact to consider:

A big gap between one persons flexibility and mobility increases the risk of injuries by a lot.

If for example your lower limb muscles such as hamstrings, VMO and quats as well as the ACL and other tendons around the knee are very soft and loose, but you are lacking strength and motor control in the legs, the risk of knee injuries increases a lot. That is the main reason why women are very vulnerable for ACL torn: Their high estrogen production causes soft, flexible tissues, but they often lack strength and a sense for movements.

Therefore: Work on both, flexibility and mobility. They should be strongly developed and proportional to each other.

But how to train Flexibility and Mobility?

  • Flexibility: long, passive holds; use bands or a stretching buddy to create external impact; use foam roller and lacrosse balls to massage soft tissue

  • Mobility: mimic the position of a joint you actually want to achieve (e.g. do deep airsquats, squat therapy etc. before a backsquat) stay active, move quickly through positions, try yoga flows

Typical Flexibility drills:

Typical Mobility drills:

Funfact: 10 Elements of Fitness

Funny enough, in the famous “10 Elements of Fitness” the CrossFit training methodology is based on, flexibility is mentioned while mobility is not. As much as I love this list for its logic and completeness, I think that one was a small Wooops by its creators. Mentioning the mobility instead would have contained the flexibility already since a mobile body is also flexible by definition. And, also, great flexibility gets you no where in CrossFit - while mobility does.