Proprioception — from Latin proprius, meaning "one's own," and perception — is one of the human senses.  Rather than sensing external reality, proprioception is the sense of the orientation of one's limbs in space and is different from the sense of balance.  Balance is derived from fluids and organs in the inner ear (the vestibular system) in conjunction with vision and other systems in the body and is called equilibrioception.  Proprioception is often overlooked as one of the senses because it is so automatic that our conscious mind barely notices it.  It is one of the oldest senses, probably even more evolutionarily ancient than smell.

Proprioception doesn't come from one specific organ but from the nervous system as a whole.  Its input comes from thousands of sensory receptors inside the body.  All of these mechanoreceptors inside the muscles and joints of the body constantly relay information to portions of the central nervous system (CNS) made up of the spinal cord and lower brain.  The CNS processes this information to allow the body to know its position in space and also to allow the brain to ‘plan’ the next movement.  All this processing is done in milliseconds which makes it seem instantaneous.

Learning any new motor skill involves using our proprioceptive sense.  Anything that involves moving our arms or legs in a precise way without looking at them invokes it — baseball, basketball, painting, you name it.  Learning a new exercise is the same as learning a new piano song; the first time you play it, it sounds like garbage!  Fortunately, this means that the proprioceptive ability can be trained, as can any motor activity.  If this is true, then it means proprioception is essential to neuromuscular efficiency and thus physical performance. 

Neuromuscular efficiency is the ability of the nervous system to ‘talk’ to our muscles to make them contract/expand.  However, at times, the motion of the body looks nothing like the picture in the mind.  An example of this would be the first time someone throws a baseball to another person.  As this activity (especially aiming at a target) involves a high amount of proprioceptive ability, the person usually looks awkward and also misses the target.  This is a result of a neuromuscular deficiency.  This deficit is caused by a lack of communication between the muscles and CNS.  The CNS cannot control the muscles if the mind has no idea where the joints and limbs are in space!

To understand the application of proprioception to fitness, let’s further explore how the system works.  Consider the previous example of throwing a ball.  The mind stores activities in the brain like files on a computer.  The act of throwing a ball is a stored sequence of muscular commands.  A preset list of commands is exactly like a computer program.  This means that your brain has a “throw ball” program saved inside it.  Every time your body wants to throw a ball it loads that program into your brain from memory.  (The concept is just like riding a bike – once the program is written in your brain, you never forget.)

So where does proprioception come in?  Remember, proprioception is the body’s ability to know where everything is.  During the act of throwing the ball, all those mechanoreceptors are giving the brain feedback at almost instantaneous speeds.  The cerebellum (a part of the lower brain) and the spinal cord process these signals from all the mechanoreceptors in the body.  The cerebellum then integrates this data with “throw ball” program all in real-time.  The cerebellum can do this as it possesses the fastest neurons in the entire body.  Through optimization, the “throw ball” program gets revised, improved, and more efficient in controlling the muscular system through the motor neurons.  This not only improves the skill but also improves general neuromuscular efficiency.  This is why every time someone repeats any activity, they get better at it hence the phrase “practice makes perfect”. 

Another benefit from this optimization is the body’s ability to practice adaptation.  Using the same example of throwing the ball, what if the ball is a different size?  What if the ground surface is different?  What if the person is not wearing any shoes?  The person can still throw the ball as the proprioceptive sense informs the body of any different circumstances using the body’s mechanoreceptors.  All of this proprioceptive data is processed by the cerebellum.  This integration of all the data immediately conditions you to adjust to the different circumstances.  This also allows the body to ‘plan the next movement’ of motor neurons regardless of the situation.  It then records the data in the brain to further optimize the program just in case the body experiences that particular situation again. 

Often overlooked, the nervous system is the most important system regarding physical activity.  Without it, all muscular performance is compromised.  By increasing the difficulty of proprioception, it is possible to train the nervous system to control the muscles with extreme efficiency and increase all aspects of muscular performance. 

This is exactly what PROTOGYM does.  It measures the difficulty in proprioception based on the activity and then increases the proprioceptive difficulty over time to maximize neuromuscular efficiency.  Through efficient neuromuscular communication, any physical performance goal can be achieved.