People don’t normally think about flexibility when it comes to fitness but flexibility is a huge part of functional movement and of improved performance.  In fact, I think it is fair to say that flexibility is integral to fitness and to health.  As everyone knows, one of the main challenges in aging is pain in the muscles and joints and a lack of mobility.  The more flexibility you maintain, the less pain and mobility problems you will have.  I will go further and say that I believe flexibility to be as important as cardiovascular fitness and strength.

Technically speaking, flexibility is defined as the range of motion possible surrounding a particular joint.  So in order to understand the potential for this type of movement, we first need to understand joints.

A joint connects bones with cartilage and ligaments.  The synovial joints, also referred to as diarthrosis joints, contain fluid and are freely movable.  They include the hinge joints and the ball and socket joints. We will focus our attention on these two joint types since they are the primary joints that allow motion to occur in the body.

Hinge joints can perform flexion and extension, like the knee does when we lift or lower the body or the elbow does as we bend the arm to pick up a weight.

The ball and socket joints have increased potential for movement because of the design of the joint and the number of muscle attachments.  They can move in circular motion like when a softball pitcher throws a pitch.  Or they can rotate up and down, in and out, with the wrist rotating in many directions, just like when you play ping pong.  The ball and socket joint can also create abduction and adduction by moving away from or toward the midline of the body.  An example of this would be when you do standing side lunges.

It is extremely important to maintain good flexibility in your various joints.  Not only will inflexibility increase the risk for injury for the joint and the muscle, but limitations of movement in sport affects both performance and musculoskeletal health.

These movement limitations, generally, can be caused by ligament tension, poor muscle flexibility and touching of soft tissue such as the calf against the hamstring or soft tissue of the torso touching the thigh when stretching the hamstrings.

There are additional factors that impact your functional flexibility.   For example, age and inactivity are critical variables.  Obviously, you cannot do anything about your age but you can do a lot about how active you are.   Not only do you need to work out on most days of the week, you need to be physically active throughout the day.  If you work at a desk job, it will be very important that you get up and move around about every 30 minutes.  If you have a physically demanding job like running a gym or you work in retail and are on your feet all day, make sure you stretch the major joints periodically throughout the work day.

Gender can also play a role in flexibility due to men having more muscle mass than women.  Generally speaking, men are less flexible than women, for this reason.  Body types like endomorphs and ectomorphs will vary in flexibility based on muscle mass and size.  Research supports the fact that overdeveloped muscles may encourage less flexibility if stretching is not included but discounts the myth that muscular size alone restricts flexibility.

If you are unsure of the level of your individual joint flexibility, we suggest you test yourselves.   You can measure the potential of movement of these joints using different planes including the sagittal (left/right), frontal (front/back) and transverse (upper/lower) body planes.  There are flexibility tests for most joints in the body.   Fortunately, there are many sites on the Internet that will help you measure your various joint’s flexibility levels.   One good site that helps you walk through the various flexibility tests is

The most common test is trunk flexion which is measured using a “sit and reach” test. 

Trunk extension evaluates the backward bend of the spine in the lumbar area. 

Hip flexion tests the range of motion of the hip and hamstrings. 

Shoulder flexibility measures the multi-rotation of the ball and socket joint in the shoulder and is very helpful in swimming, racquet sports and throwing sports. 

I hope you can see from this discussion why flexibility is so important.  In our next blog installment we will begin to learn how to create flexibility in our body through stretching exercises.


Published by Sadie