Stability, Mobility & Flexibility 

How proprioception, the vestibular system and visual acuity work to support these functions.
Written by Jenn Giamo


I promise this post will not be as technical (or boring) as the title suggests. Its purpose is to help you understand why these 3 components of fitness are important, how to improve your stability, mobility and flexibility and enhance functional performance and overall longevity.

When we’re young and active and injury-free, we don’t always give much thought to functional movement. We want to be faster, leaner, stronger and fitter. We want the elusive 6-pack abs and bikini body. But what if we were to look ahead 10, 20 even 30 years? There is no reason you have to give up marathons for mini-golf so how can we stay injury-free and maintain our fitness as we age? 

This is where the importance of stability, mobility and flexibility come into play. Since we mistakenly use these terms interchangeably, here is some clarification according to and

STABILITY is defined as the ability to maintain control of joint movement or position by coordinating actions of surrounding tissues and the neuromuscular system. Joint stability depends largely on the shape, size, and arrangement of the articular surfaces (the surfaces on joints and cartilage where the bone makes contact with another bone), the surrounding ligaments, and the tone of the surrounding muscle.

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MOBILITY within a joint is the degree to  which the area where two bones meet (articulation) is allowed to move before restricted by the surrounding tissue such as tendons, muscle, and ligaments. Think of mobility as the range of uninhibited motion around the joint.

A good level of mobility allows a person to perform movements without restriction, while a person with good flexibility may not have the strength, coordination, or balance to execute the same movement. Good flexibility does not always mean good mobility.

FLEXIBILITY is the absolute range of motion in a joint or system of joints, and the length of muscle that crosses the joint involved. It directly correlates  with range of motion and mobility, but does not directly correlate with strength, balance, and coordination. Range of motion is the distance and direction the joint can move, while mobility is the ability to move without restriction.

So as you can see, each of these components together are integral in creating sound movement patterns. Having good flexibility alone will not prevent or heal injuries just as mobility and stability independent of each other will not yield optimal results. It’s important to think of the connective tissues, muscles and bones surrounding the joints as an integrated system and the health of one joint relies on the health of others.


One of the influencers of these components is proprioception. 

PROPRIOCEPTION is the sense of knowing where your body is in space without having to look at it. For example, if you close your eyes and raise your arm above your head, you don’t need to see your arm to know that it is above your head. By using the receptors located in the skin, muscles and joints, proprioception builds a sense of internal awareness. This awareness allows us to maintain our balance and stability during movement. You can sharpen your proprioceptive skills by practicing exercises which can help in preventing injuries to your body by making it adaptable to your changing environment. 

The types of exercises to improve proprioception function include:

Exercises While Closing Your Eyes: As you gain more confidence, you will be able to perform your activities with your eyes closed. This will help to enhance the communication/coordination between your brain and muscles which will further make you capable of knowing where your body parts are without looking at them.

Strengthening Exercises: As you know, strengthening exercises like lunges and squats help in making your muscles stronger. As the muscles get stronger, the brain starts to recognize their strength. This strength helps improve proprioception awareness of the mind and the body.

Plyometric Movements and Drills: Exercises which incorporate coordination and movement help to enhance kinesthetic awareness. As your body moves, the brain eventually gets trained to respond to these movements. Then, over a period of time, we are able to perform activities with more confidence and less fear.

Vestibular function is your ability to sense the position and movement of your head in relation to gravity. The vestibular system provides sensory  perception for spacial orientation while standing upright. When the angle or surface that you are standing on changes, vestibular inputs are used to recognize these changes. It is your inner ear that uses the vibrations to create nerve impulses that travel to your brain in the form of sound while also contributing to balance and stability.

According to a 2016 study by Massachusetts Eye & Ear, published in Science Daily, “Vestibular thresholds begin to double every 10 years above the age of 40, representing a decline in our ability to receive sensory information about motion, balance and spatial orientation.”

In order to maintain the health of your vestibular system, try performing exercises on a balance board or on a small base of support. This will facilitate the use of vestibular inputs and help to improve balance and stability.

Visual Acuity is a bit more obvious, right? The clarity of our vision determines how we perceive things including the way our bodies move. By  clearly seeing what is in front, below or beside you, your body can make adjustments accordingly. We rely on our vision when performing all kinds of exercises including foot placement in yoga poses or hand position when boxing, which helps us to avoid injury and maintain proper form. Our visual  acuity works in conjunction with vestibular function and proprioception so that our bodies can perform optimally in any environment. 

To maintain good vision and strengthen the muscles of your eyes, try the following techniques:

Eye Shifting: Look to your right corner and then shift your gaze gradually to the left corner. The tiny eye muscles get more active and healthy with the as blood gets pumped in from the shifting.

Figure 8: With your arm outstretched and your thumb pointing up, keep your head still and focus your eyes on the thumb. Draw a figure eight with your thumb, keeping the elbow straight.

Blinking: Sit comfortably with your eyes open. Blink 10-15 times very quickly. Close your eyes and relax for 20 seconds. Repeat this 4-5 times.

So now that you know the importance of stability, mobility and flexibility in maintaining an injury-free, active lifestyle, let’s discuss some exercises that will enhance these functions while employing proprioception, vestibular function and visual acuity (that’s a mouthful) systems. 

Since this is a blog post and not a thesis, I am not going to cover all of the joint and muscular systems of the body but instead focus on the core. Many people think of the core as simply the abdominal muscles (or 6-pack) but it involves much more than just the abs.The core is our center of gravity by which all movement is influenced and it functions to stabilize the trunk while the arms and legs move.

When we view it this way, we see that the core actually includes:

  • Muscles that stabilize the hips

  • The system of muscles that make up the torso (on the front, the sides, and the back of the body)

  • Muscles that stabilize the shoulders

The core is responsible for 2 major jobs; to protect the spine from overload and to transfer force between the upper and lower body. 

For stability purposes, it’s important to use functional exercises with small ranges of motion or isometric contractions instead of old-school sit-ups or side bends. These exercises are my favorite for stabilizing the core:

  • Plank: on your forearms and toes (feet together or slightly wider) keeping the back elongated and the head and neck in line with the spine; abdominals are pulled in and there is no sinking into the lower back or lifting up in the hips.

  • Side Plank: start by lying on your side, coming up onto your forearm with straight legs stacked on top of one another; lift hips up and keep your body in one straight line from head to toe.

  • Bridges: Lying on your back with knees bent and feet flat on the floor; hands at your sides; press into your feet as you lift your hips up; squeezing the gluteal muscles and engaging the pelvis.

(Proprioception involved in contact with forearms, feet and back on the floor)

For mobility of the core, we can keep it simple and you can perform the same exercises above with the addition of movement.

  • Plank: similar to the position as described above but coming up to your hands (push-up position); keep the core braced and breathe deeply. Slowly, draw the right knee in toward the chest and release the foot back to the starting position. Alternate between driving the right and then the left knee forward.  

  • Side Plank: same as above but begin to drop your right hip towards floor (without resting it) and then back up towards the ceiling and in line with your shoulder. Repeat on the left side.

  • Bridges: same as above while lifting and lowering the hips to the floor.

(Vestibular Function employed as movement occurs during each exercise, sending signals to the brain, maintaining center of gravity)

  • Spinal Rotation: While seated in a chair, rotate your torso to the left and grasp the back of the chair with both hands. Tense your core muscles for 5 to 10 seconds, then release the tension and press into the chair with your hands to turn slightly farther. Repeat this contraction/relaxation cycle several times, then repeat in the opposite direction, rotating to the right. This will improve flexibility in the abdominal muscles and lower back which rotate your torso right and left.

  • Leg Crossover Stretch: The leg crossover stretch targets the gluteal muscles involved in hip abduction, extension and rotation. The exercise also stretches the obliques on the sides of your abdomen. Lie on your back with your knees bent and feet flat on the floor. Extend your arms straight out, resting them on the floor. Lift and extend your left leg, then cross your left ankle over your right knee. Press into your right knee to push your leg out more, deepening the stretch through your buttocks. Rotate your hips to the right, keeping your arms and shoulder blades on the floor. Move your right knee toward the floor as you twist, and place your left foot flat on the floor, just outside your right knee. Hold this position 15 to 30 seconds, then repeat on the other side.

  • Standing Oblique Stretch: Begin standing tall and extend both arms over your head, clasping your palms together. While leaning to one side, gently pull on the opposite arm until you feel a stretch extending down your entire side. Hold for 15 seconds and then switch sides.

(Visual acuity is important in the spinal rotation and standing oblique stretch as your eyes will want to focus on a stable point to minimize dizziness or maintain balance)

I realize there is a lot of information to digest in this simple blog post, so please ask questions. To learn more about your specific concerns, I encourage you to sign up for The Home Stretch where we assess muscular imbalances and range of motion to provide an assisted stretching routine designed just you!

Amanda Gay