As a kid, I [Doug] can remember hearing a joke that my father told me. As you can likely relate to, I wish I could remember half the jokes that I hear. This one joke, though, I can remember, which serves as a great jumping-off point to this blog.
This particular joke, when I researched it, has many different angles and characters, yet with the same punch line. Instead of trying to retell it in my own way, I thought that Comedy Central delivered a nice, tactful way of telling it. Here it is:
“A newspaper reporter went to interview an old man who was the last person in the county to have lived through the Civil War.
Thinking he had a story, the reporter started asking some questions.
‘Sir, you have lived through the civil war and two world wars. You have seen the invention of the automobile and the airplane. In all of your days, what would you say is the single most interesting thing you have seen in all of your days?’
The man replied, ‘The Thermos.’
Puzzled, the reporter asked, ‘Why?’
‘Well,’ the old man responded, ‘when you put something hot in it, it keeps it hot. When you put something cold in it, it keeps it cold ... HOW DOES IT KNOW?’”
How does it know?! I love it!
Speaking of “How does it know,” this reminds me of the Pacinian Corpuscles. These proprioceptors respond greatly to changes in velocity – speeding up or slowing down. The thing about them, though, is they do not know if the body – the movement – is speeding up or slowing, only that it is changing.
While the thermos does not know if the contents are hot or cold, it does know how to maintain the temperature. While the Pacinian Corpuscles do not know if the speed is greater or less, they do know that the body needs to adapt.
Pacinian Corpuscles are another type of mechanoreceptor that contributes to the neural representation of body position and movement that we call proprioception. The terminal endings of the afferent nerve are encapsulated like many other proprioceptors. Pacinian Corpuscles have been found in the skin, ligaments, and joint capsules throughout the body. They have a greater density in the soles of the feet and the palms of the hands.
The Pacinian Corpuscles, classified as Type II receptors, have a structure at the end of the nerve that is different from other proprioceptors. The structural differences imply a unique role for these mechanoreceptors. The challenge is to understand what essential information is being provided by the Pacinian Corpuscles, and how this will influence the training and rehabilitation programs designed by movement specialists.
Pacinian Corpuscles respond in a unique way to mechanical stimuli created by movement and other physical forces. They have been described as responding to velocity, but because of their response characteristics, it is the change in velocity that the discharge of these receptors infers. Pacinian Corpuscles have a very low threshold. This means that they are sensitive and will discharge with very little change. Research also shows that they adapt to the mechanical stimulus very rapidly. This means that the Pacinian Corpuscles stop firing even if the initial stimulus is maintained. They have been compared to an “on-off” switch that fires when the current conditions change. The afferent impulse does not indicate either “on” or “off.”
So what are the functional implications of this knowledge? A change in velocity (either faster or slower) will cause the Pacinian Corpuscles to discharge. This strongly suggests that the Pacinian Corpuscles signal acceleration or deceleration, but not specifically which one. Only combined with the neural signals from other proprioceptors does the “proprioceptive picture” of movement become clear.
The structural uniqueness of the Pacinian Corpuscles influences discharge response. The encapsulated end has a design that dampens low-frequency signals before they reach the nerve ending but allows high-frequency signals to pass right through. Studies have shown that Pacinian Corpuscles are very responsive to high-frequency vibrations that could indicate movement. This has led researchers to propose a role of providing additional information about movement through the increased density in the soles of the feet (surface contact) and palms of the hand (objects that we grasp).
Even with our limited understanding, knowing that Pacinian Corpuscles respond to a change in velocity will influence our strategies for designing functional assessments and training programs. Fortunately for all practitioners, normal functional movements contain the natural acceleration and deceleration stimuli that the Pacinian Corpuscles require to contribute to the neuro-perceptual information that some researchers refer to as the “body map.”
So what, who cares, why is this information so important? Gray Institute® has coined many phrases, including the following statement: “Movement turns on proprioceptors, proprioceptors turn on muscles, and muscles control the movement.” The proper (functional) movement is key, which is why 3DMAPS® (3D Movement Analysis & Performance System) is so vital to any assessment and any progression/program.
The Analysis Movements of 3DMAPS® require acceleration and deceleration of all the joints simultaneously. The Analysis Movements are driven by the “Pacinian-dense” feet and hands. Tweaking the Analysis Movements, through the Performance System of 3DMAPS®, by changing the speed of the movements and adding load to the hands will accentuate the discharge of the Pacinian Corpuscles. The plane-dominant Analysis Movements can be combined to replicate specific functions, while emphasizing rapid change of direction, as a strategy to improve the effectiveness and efficiency of our client’s function.(Learn more at https://grayinstitute.com/courses/3dmapsthree-dimensional-movement-analysis-and-performance-system.)
Some examples within the Performance System are “Pivots (In-Sync)” and “Pivots (Out-of-Sync).”
Pivots (In-Sync) allow for the Sagittal Plane’s two (2) Chain Reaction® Movements (Anterior Lunge with Bilateral Hands Posterior @ Overhead Swing and Posterior Lunge with Bilateral Hands Posterior @ Ankle Swing) to be combined into one movement. The same logic applies to the Frontal Plane’s two (2) Chain Reaction® Movements (Same Side Lateral Lunge with Bilateral Hands Opposite Side Lateral @ Overhead Swing and Opposite Side Lateral with Bilateral Hands Same Side Lateral @ Overhead Swing) and the Transverse Plane’s two (2) Chain Reaction® Movements (Same Side Rotational Lunge with Bilateral Hands Same Side Rotational @ Shoulder Swing and Opposite Side Rotational with Bilateral Hands Opposite Side Rotational @ Shoulder Swing). Each load and explode of one (1) direction feeds the load and explode of the other direction. This allows for the mass to generate more momentum within the new, combined movement, thus igniting more Pacinian Corpuscles.
Pivots (Out-of-Sync) generate a new movement pattern that the body may not be as used to when compared to the In-Sync movements. In the Sagittal Plane, the Anterior Lunge with Bilateral Hands Posterior @ Ankle Swing and Posterior Lunge with Bilateral Hands Posterior @ Overhead Swing are combined into one movement. In the Frontal Plane, the Same Side Lateral Lunge with Bilateral Hands Same Side Lateral @ Overhead Swing and Opposite Side Lateral with Bilateral Hands Opposite Side Lateral @ Overhead Swing are combined into one movement. In the Transverse Plane, the Same Side Rotational Lunge with Bilateral Hands Opposite Side Rotational @ Shoulder Swing and Opposite Side Rotational with Bilateral Hands Same Side Rotational @ Shoulder Swing are combined into one movement. Again, each load and explode of one (1) direction feeds the load and explode of the other direction. This allows for the mass to generate more momentum within the new, combined movement, thus igniting more Pacinian Corpuscles.
When it comes to movement, it is all about purpose. Applied Functional Science®, through its Principle-Strategy-Technique Process, allows you – the movement specialist – to come up with the right movement for the right result for the specific individual. In this scenario, why would one use the Pivot (In-Sync) and Pivot (Out-of-Sync) movements? Among many reasons, to (1) facilitate ongoing success for the individual; (2) allow the body to experience all planes of motion in a way that is parallel to life; and (3) turn on Pacinian Corpuscles in an authentic manner. By the way, this can be the answer to all movements in 3DMAPS® for not only the Pacinian Corpuscles, but also all the proprioceptors!