Mobility vs Flexibility - What's the Difference?

Mobility vs Flexibility - What's the Difference?
Guest blogger: Narina Prokosch, RN CPT

Often during our warm up routines at the gym, clients will mention feeling a stretch in certain muscles during some of the drills. This will then lead to an explanation of what it is we are hoping to accomplish during the warm up and what you should be feeling. As you may know, we go through several drills prior to a more dynamic warm up that will lead into the strength portion of your workout.  The drills are specifically designed to increase mobility through a joint.  You need a certain amount of mobility or the ability to move your joints through a normal range of motion.  But what is mobility and what is flexibility?

In a nutshell mobility is the ability of the joint to move through a range of motion and flexibility is the ability of the muscle to stretch to allow movement.  In this article we are going to deal with mobility.  Physical Therapist Gray Cook's analysis of the body and its function is by means of a series of joints.  Each joint has a specific function and is prone to specific dysfunctions.  He evised a table that describes the body on a joint-by-joint basis from the bottom up:

Ankle Mobility
Knee Stability
Hip Mobility
Lumbar Spine stability
Thoracic Spine mobility (upper back)
Gleno-humeral stability (shoulder)

As you can see from this chart the joints alternate between mobility and stability.  Injuries and problems occur when the joints lose the ability to perform their specific function be it mobility or stability.    For those of you that train here at VWP, you will all have gone through ankle range of motion testing.  To refresh your memory, you were kneeling on the floor in a lunge position.  We asked you to push forward with your knee over your toe, keeping your heel down.  We then used a stick from knee to ground to measure distance your knee moved past your toes.  

We know that a good range of motion for the ankle is 4" or more past your toe.  If your ankle lacks the mobility it needs, when  we ask you to perform exercises such as squats or lunges, you either will not be able to perform these exercises correctly , or you will get knee pain when you do perform them.  For this reason, we have included 3 specific ankle mobility drills (ankle rolls, knee to wall, toes on foam roller) in your warm up routine.  We also know in our own unscientific test that performing these ankle drills does work.  We had one client go from 1/2" ankle mobility to 3" ankle mobility in both ankles in a 3 month period.

The hips must be mobile in all planes of movement (front to back, side to side and rotational).  If the hip loses its ability to be mobile, you get low back pain.  Most lower back pain is not caused by a weak back, it is most often caused by a tight and immobile hip. To work on increasing hip mobility, we will go through a series of hip drills (leg swings front to back and side to side; wide squats).  With some clients we will also use a form of lunge on a block.

This exercise is called a dynamic warm up in that we are using body weight and a little momentum to increase the range of movement in the lunge.  We also use everyone's favorite exercise - the Bulgarian squat - to increase the hip's range of motion.

The lumbar spine or "low back" needs to be stable.  Great strides have been made in recent years in understanding the function of low back.  Shirley Sahrmann and Porterfield and De Rosa (3)say that increasing range of motion through the lumbar spine isn't recommended and can be dangerous.  For those of you who train at  VWP you will notice that we do not do rotational exercises where the pelvis is staying locked and you are twisting side to side.   Our warm up at the very beginning of your program is rotating, but you will also remember how Kevin and I are constantly monitoring this exercise to ensure your whole hip and foot are rotating to the direction you are moving the ball.  

So, the rotation is happening through the hip, not the lower back.  Also for you golfers, the cable chop exercise is also done rotating the hip and foot to the  direction you are moving.  In other words you are "leading with the hips" not the lower back or the shoulders.   Also, for the golfers, some of you perform the Diagonal Plate Raise exercise.  And, yes this is one exercise that we are rotating, but very specifically and again no rotation through the lower back.

About the Author
Narina Prokosch, RN CPT is a Registered Nurse and Certified Fitness Coach from Victoria, BC Canada.  She is the owner of Victoria Wellness Professionals, a private premium level Fitness Coaching Facility.  Narina has a background in bodybuilding and equestrian sports.   Narina encourages "monitoring, mentoring and motivation" with all her clients.