Mobility vs. Flexibility

In reality, mobility and flexibility are two very different concepts and are thrown around as buzzwords without a true understanding of how they apply to the human body. In the following article, we are going to discuss Mobility and Flexibility and give you a greater understanding of these two concepts and how you should begin to think about them in your current fitness routines.


The term flexibility can be defined as the ability of a muscle or muscle groups to lengthen, and often described as the extensibility of the muscle tissue. Two key takeaways on flexibility:

  1. Flexibility is isolated in nature and doesn’t address how that particular muscle is functioning when asked to work in coordination with other muscles for complex movement.
  2. Flexibility can be looked at both as active and passive flexibility. Active flexibility of the hamstrings can be examined when you reach down and touch your toes. The hamstrings are loaded with tension and asked to lengthen to provide Range of motion (ROM) into that movement. Passive flexibility of the hamstrings can be assess while on a table with a practitioner moving your straightened leg through hip flexion. In this example, the tissue is not loaded and isn’t working in series with other muscles to produce the ROM.  The key take away is that you can have great passive flexibility but poor active flexibility. We’ll talk about this shortly.


Mobility is defined as the ability of a joint to move actively through its intended range of motion. It is global in nature and effects every aspect of our movement quality and function. Although the qualities of mobility are also determined by the structural integrity and kinematics of the joint structures, today we will focus on the soft tissue qualities that impact joint mobility. Specifically a muscles length , strength and function.

Two key takeaways on Mobility:

  1. Flexibility is a component of Mobility. The ability for a muscle or groups of muscles on one side of a joint to lengthen, while muscles on the opposing side of the joint are shortening (contracting), produces movement and impacts the degree of mobility. Example: Often times the mobility of the hip joint into extension is impacted by the stiffness of the Hip Flexor complex. If the hip flexors cannot lengthen optimally, it effects the ability of the glutes to properly contract and bring the hip into extension. Often times increasing the extensibility of the hip flexors leads to better glute function and therefore improvements in hip mobility.
  2. In order to have mobility, there must be adequate strength and stability present into the range of motion we are moving.If we cannot stabilize and control the moving parts involved, both isometrically and eccentrically, our body will not grant us access to the desired range of motion.  It functions as a protective mechanism that says, “I feel unsafe and unstable into these ranges “and in order to avoid injury, it keeps us out of compromising positions. This is why every complex exercise you do with proper technique like a squat or a deadlift, acts as a mobility exercise because you are training the body to feel strong and safe into those positions.

In closing, often times I see people working to improve their movement quality and Range of Motion by attacking it with flexibility interventions only and thinking, “if I stretch my hip flexors, my back pain or limitations in hip ROM will go away”.

The reality is that we need to be focused on improving mobility. Flexibility is only one part of the equation to build a fundamentally sound body and promote and sustain joint health. We can have great flexibility but poor mobility; so shifting focus to controlling the flexibility we develop or that already exists is the key to improving mobility and having healthy pain free joints. When we increase stable, usable Range of motion through improvements in joint mobility, we limit movement compensations and limitations and improve joint health. In the next article, we will dive in deeper and look at how flexibility interventions as well as strength help to develop better mobility and in turn, healthy and pain free joints.