I [Doug] really enjoy humor. It is powerful, especially used in the right (and tasteful) form.
Wikipedia defines humor as “the tendency of particular cognitive experiences to provoke laughter and provide amusement.”
Instead of going deep into the neuroscience of humor and laughter, I simply want to briefly discuss one aspect of humor that can serve as a jumping point into the Golgi Ligament Endings.
On the Brain: The Harvard Mahoney Neuroscience Institute Letter had a piece on “Humor, Laughter, and those AHA Moments” (Spring 2010, Vol. 16, No. 2). In this writing, the following was stated:
“… When the punch line hits home, your heart rate rises, you jiggle with mirth, and your brain releases “feel good” neurotransmitters: dopamine, serotonin, and an array of endorphins.
Jokes work because they defy expectations.”
Yes, “Jokes work because they defy expectations” – because they catch you off guard, because things don’t end up the way you may have thought.
Movement may be no different. For example, our expectation may be to avoid motions that cause ligaments to tear. The defied expectation is, then, this: the movements that create the joint motion, which create the tension, that might cause the ligament to tear, must NOT be avoided.
Ligaments are known for the ability to limit motion. They receive a lot of attention when the forces imposed on a ligament exceeds its ability to resist, resulting in a tear / rupture. Ligaments can take the form of a separate structure or a thickened reinforced section of a joint capsule. In either form, the ligaments have sensors that respond to tension. The presence of these sensors insures that the role of ligaments goes well beyond functioning as a passive restraint of motion.
Ligaments have been shown to have at least four (4) different types of sensory endings that contribute to proprioception. Historically, some of these have been called Golgi Ligament Endings because they are encapsulated (Golgi-like) and are present in the ligaments. There are two (2) types of these found in ligaments: Type I and Type III. These sensory receptors provide important proprioceptive information to the body to guide coordinated movement. The important difference between the Type I and III endings is that the threshold of tensile force required for the sensory ending to fire is different. The Type I endings have a lower threshold than the Type III endings. This difference has important implications with regards to the use of this information by the body during functional movements.
The role of the Type III endings may be to sense when tension in the ligament is approaching the tissue limit. Because of the higher threshold, these endings would not fire until the tension approaches the strain limits of the ligament. A rapid reconfiguration of the muscle synergy may be necessary based on information from the specific ligament along with the other proprioceptors throughout the body. Hopefully this creates an altered movement that protects the ligament (and other structures) from injury.
The Type I endings, with the lower threshold, will be discharging during all types of activity under normal tension loading. Logic would suggest that their role is not safety, but rather contributing to the efficient execution of functional movements. The importance of this sensory information necessitates that movements be designed that create tension in a ligament rather than avoid this type of movement stress.
A less understood, but potentially critical, function of these Golgi Ligament Endings is the fact that these ending influence the muscle spindle. The discharge from the muscle spindle afferents is altered when tension is added and then removed from joint ligaments. So tension in the ligament would directly influence the muscle spindle, which would then influence the motor output from the muscles.
Eventually, there will be more specific evidence from research about the type of information sent from Golgi Ligament Endings. Our understanding of how this sensory information is integrated and used by the body will improve. What will not change is the “truth” that it is essential to utilize authentic functional movements that provide controlled stress to ligaments in training, rehabilitation, and injury prevention programs.
The functional implication of the structural truth about Golgi Ligament Endings is this: the movements that create the joint motion, which create the tension, that might cause the ligament to tear, must NOT be avoided. Successful programs will start with movements where the client is successful, while planning to create the ligament tension by gradually increasing the challenge in terms of motion, load, and / or speed. The medial collateral ligament (MCL) of the knee can serve as a very helpful example of how these concepts would be realized.
The MCL provides resistance to knee abduction (valgus) and external rotation. The resistance produces tension, and tension causes the Golgi Ligament Endings to discharge. Both of these motions are frequently part of weight-bearing activities. So too much motion can tear the ligament, but “just the right” motion is perfectly normal. So training movements that cause abduction and / or external rotation should encouraged. In fact, training movements that cause the MCL to be under tension is the best way to reduce the chances of injury. To complete the “Goldilocks” analogy, too little tension in the MCL will not provide sufficient sensory information. This deficit in information may turn into a detriment to function.
If we believe, to any extent, in the need for the MCL to “experience” tension, then the strongly held admonition that the knee should never move inside the middle of the foot becomes exposed as a dangerous fallacy. From a structural standpoint it has been shown that after injury, the MCL heals much better when is it is exposed to gradual tensile stresses. From a neuro-perceptual standpoint, if the valgus position of the knee is avoided during training, but will be present during function, then we as movement specialists have set up our patients and clients for failure.
Imagine that the proprioceptive synthesis created during movement has not “heard from” the MCL during training. Then during functional three-dimensional movements, the knee goes through abduction and external rotation. The Type I (and maybe even the Type III) endings will discharge, sending afferent information. Some questions, then, to consider are as follows:
- Where was this input during training and rehabilitation?
- Does this information create “confusion” rather than “clarity” about the specifics of the movement?
- Could our well-intentioned programs of avoidance be part of the “problem” instead of a component of the “solution”?
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.
When it comes to any and all movement, it is a must to begin with success. Based on this success and the goal of the movement, changing the movement to progress the movement is imperative. Gray Institute® refers to this as “tweaking” the movement. Additionally, Gray Institute® believes that the small tweaks are the most powerful tweaks.
Tweaks are leveraged in the Performance System of 3DMAPS®. The progressions systematically enhance the mobility and stability of the body in a successful manner. Two such progressions we would like to call to your attention are “Plane (Hands)” and “Plane (Foot).” These tweaks / progressions mix and match the six (6) lunges (Anterior, Posterior, Same Side Lateral, Opposite Side Lateral, Same Side Rotational, and Opposite Side Rotational) with the six (6) bilateral hand swings (Posterior @ Overhead, Posterior @ Ankle, Same Side Lateral @ Overhead, Opposite Side Lateral @ Overhead, Same Side Rotational @ Shoulder, and Opposite Side Rotational @ Shoulder). Why? To simulate movement the way it happens in real life – when all planes of motion are being mix and matched to accomplish a variety of tasks. (Learn more at https://www.grayinstitute.com/courses/maps.)
Take the knee – the MCL – for example. It is NOT that it doesn’t want the knee to abduct, but it DOES want to control this motion. The variety of movements in the “Plane (Hands)” and “Plane (Foot)” allow for the MCL to experience this motion (with other motions of the knee) in a manner that is safe and functional. The beauty, too, is that all the primary complexes of the body get to experience similar inputs and outputs.
When it comes to movement, take a second to consider if traditional ideas (keep the knee over the foot, neutral spine, consciously make your muscles work, etc.) are what really happen in function or if they, while well intended, are a joke. We, as movement professionals, need to challenge everything and, potentially, defy traditional expectations for the benefit of our patients and clients. Our training and rehabilitation must set the individual’s body up for success and be given the best opportunity to not get injured.