By Lee Jarvis M.OMSc. Proofreading and editing by Eric Kamta.
It is a commonly known fact in the manual therapy world that generating effective long leverage is a difficult thing to learn. Learning how to be effective using the long levers of the body takes many years and some argue that there is always more to learn. Some even call the use of long leverage dangerous and a practice to be avoided entirely. The author disagrees with the idea that long leverage should not be learned, but can understand why some believe it is dangerous (though this is not the subject of this article). The difficulty in learning to effectively create levers would appear to be at least in part due to the complexity of the system and the materials it is made of. Whether at the start of your learning or years into it, a critical review can help make sense of the effort it takes to learn this valuable skill and validate the frustration that is often a necessary part of the learning process.
The concept of levers or leverages is often covered fairly early on when learning basic musculoskeletal anatomy and biomechanics. This education often includes the parts and components of the type 1, type 2, and type 3 levers.
The most classic example of all the leverage types being the type 1 lever with a rock, a small log for a fulcrum (which we will call “fixed point” hereafter), and a long branch for the lever arm.
This is likely the most common example of a lever as the components and use of the lever is easy to understand. As easy as it is to understand, it is likely that most of those reading this article are not farmers (the author included) and our tractors are rarely blocked by boulders on the road. This being the case, the teaching of levers which is usually done only conceptually, is now taking place in a lecture hall or via video. What is not often considered when mentally constructing a lever system from physical objects is that you must actually have all of the necessary physical objects. Second to this, should you be able to acquire these physical objects, they must all be capable of doing their intended job. Finding a load to move of course necessitates the commencement of the parts finding process. If you do not have something that cannot be moved without a lever, you would not be looking for a wedge and a stick. However, finding a really good lever arm is probably more difficult than we make it out to be. Sticks and branches are available only if you live near numerous trees or perhaps a garden centre that sells “decorative” branches (for substantial up-charges). Once you have found that branch, the length of the branch must be long enough to work. A lever arm too short may not generate the necessary force on the load in order to move it. If the lever arm is long enough, it must also be strong enough to withstand the force necessary to do the work placed upon it by the user and the rock on opposing ends. A lever arm with low structural integrity will break when moved against a heavy load. If the lever arm is long enough and strong enough to withstand the above-mentioned forces, the next concern to raise is, can the user of the lever even generate the force necessary to move that rock with their muscular efforts? These are genuine concerns if the leverage in question were actually real but totally irrelevant when simply attempting to conceptualize the mechanics of long leverage. When it comes to the human body, there are some similar concerns with leverage, but interestingly there are some completely opposite problems.
Just as with the stick and the rock example, leverage makes it easier to move parts of the body. The most typical lever in the body is the type 3 lever, as this adds to the precise control of appendages. However, the human body does not have a lack of leverage systems, quite the contrary, we have a surplus of levers. What we see along lengths of the body is numerous interacting levers of different types, each capable of both independent and group activation.
This is only one way of looking at it, but if we take the bones as lever arms, the joints as fulcrums/fixed points, and the muscles as the force generators to move the load, you will notice that some muscles cross singular joints and others cross multiple joints. This means that the muscles crossing singular joints are acting on a single lever whereas the muscles crossing multiple joints are acting on multiple levers at once.
We also have to take into account that it is rarely just one muscle firing, muscles tend to fire in organized groups and with different amounts of force depending on what type of movement is needed. This supports the idea that long leverage is inherent to the human body, it is its preferred way of generating movement.
In Osteopathic practice, the issue of generating long leverage systems in the human body seems to be in having to use many levers simultaneously. The human body is more like having a rock to move (the lesion or somatic dysfunction), your fulcrum/fixed point which is a semi-gelatinous tissue variously shaped, and your lever arm which is more like 2-5 sticks connected by wet rubber bands at irregular lengths and angles. Also, the lever can and should tell if you use it too forcefully, which if you were taught correctly should not happen but it is still good if the patient communicates discomfort.
There are so many long leverage systems available to us in the human body because long leverage is the default way of moving. Long leverage, or anatomic parts of various hardness working in an integrated way, decreases the effort spent on movement over time. It disperses the load evenly along the body, and increases the relative strength produced by the muscles. This dispersal of force amongst the body also has a protective capacity as it tends to prevent loads from being concentrated on smaller tissues of the body that cannot withstand those loads. Long leverage is of course not unique to humans as many other animals use it just as well (and probably better in some cases).
The numerous interacting leverage systems stacked one on top of the other make it harder to concentrate load to specific areas by the Osteopathic practitioner. The body could be said to be trying to avoid this concentration normally, though it doesn’t strictly prevent it entirely. If placing/dispersing a load throughout all parts of the body is protective and increases strength, this will happen both actively and passively. To say it another way, this process of load dispersal occurs involuntarily, so when attempting to construct specific directions of long levers to a point of limited motion the body is not necessarily working with you.
When it comes to Osteopathic manual methods, wherein the practitioner utilizes the body’s levers to move body parts, assembly of these levers must take place inside the body. This means we actually don’t have any direct contact with the levers. Even if there is no clothing over the appendage, there is skin and layers of connective tissue in the way before we actually get to the real bone, joint, or muscle. Furthermore, this means the lever has to be constructed by the practitioner’s kinaesthetic sense, which you could actually say would be palpation via a long lever (a topic for another time).
I am of the opinion that the frustration typical of the Osteopathic student in their first few years of school (outside the enormous reading workload) is due to the fact that they may be able to conceive the concept of the lever, fixed point, and load in their head but entirely incapable of making it happen on the table. Again, the body will be attempting to avoid your leverage directed to the fixed point and the unmoving tissue is also resistant to lengthening (the specific goal of your lever). So, with any manual therapy method that uses long leverage to create movements in small areas, the complexity actually comes not just from assembling the parts to create leverage systems, but to specifically guide that leverage and direct its force to the intended structures.
This is why if you do not get long leverage right away you should not be too hard on yourself. Time, practice, and the eventual familiarity that comes with those things are your best teacher.
Dig on.