Defining PT Jargon

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Physical Therapists will often speak in terms from our training, but don’t always explain what they are exactly. We will use layman’s terms and analogies to get the point across. Sometimes a client wants to know more so we created this Defining PT Jargon page. We listed these common PT terms in alphabetical order to make it easier to find. Scroll on through this page to translate PT language.


The layers of tissue from the skin down through muscle and bone can become stuck together. When this happens, there is less fluid in the tissue to allow for sliding back and forth. Adhesions are like scar tissue, but they can be develop without an injury.


The way we keep parts of the body or systems of the body working together. Another term for this is equilibrium. It means to keep things just-so, in a happy place, where all functions are operating the way they were intended. Classically, we use the term balance to describe our ability to keep upright and not fall over. However, PT’s will describe balance of posture and strength. Being unbalanced means there is unevenness that throws off stability. Mechanical imbalances mean the body is off center or not aligned. When we bring posture into a better balance, then there will be more even work for the muscles and joints.


When two of more muscles engage to hold a joint of segment of the body rigid. A good example is the co-contraction of the wrist extensors and finger flexors when gripping a golf club.


Squeezing, pushing or pressing two parts together. This occurs in the spine when the weight of the head and arms push down due to the effects of gravity. Compression helps us move the way we do, but when joints break down or muscles are too tense, compression can be painful. That is why PT’s know about ways to take pressure off to relieve pain. 


Tightening of a muscle to produce force needed to complete an action. Contracted muscles have fibers overlap each other which makes the muscle shorter as it bunches up.   


When a joint or a muscle tightens up an becomes hard to move passively. It can also cause pain. This happens if a joint or muscle isn’t moved through it’s full range of motion. Typically, this will be seen after a surgery or with neurological diseases like Cerebral Palsy or Stroke.


When parts of the body work together in the right order to perform an action that requires precision. An example is walking. Each time the weight is shifted from one foot to the other, muscles have to coordinate to hold he body upright while one foot swings through the air to land back on the ground with the foot flat. Then it repeats over and over in the same fashion. 


The part of the body that commonly is referred to as the midsection. It is more than the midsection, though. The core is made of up the spine and pelvis. Plus, any muscle that attaches to the spine and pelvis is considered a core muscle. 


A special cushion that can be found between vertebrae C2-S1. The disc is made up of an inner soft core called the nucleus pulposis. It has the consistency of lobster meat that acts like a shock absorber and pivot point for movement. Wrapping around the core is the annulus fibrosis that holds the disc together. The fibers actually overlap in a woven pattern and acts similarly to a Chinese finger trap. Endplates create a top and bottom for the disc and is responsible for nourishment.

Discs are about 80% water and literally act like a sponge. In fact, our spines lose water concentration the longer our spine is upright sitting or standing because gravity will press downward from the head to the tailbone. Its like squeezing water out of a sponge. When we lie down for 20 minutes or more when sleeping for example, a considerable amount of water re-enters the disc through the endplates and plumps it back up. This is the reason for why people are taller in the morning and shorter in the evening.


A fancy word for bruising. This happens when blood vessels actually break and bleed inside the body.


Becoming whole again. In terms of an injury where there is damage, the body will perform a series of operations to repair and rebuild. There are 4 stages of healing. 1. Hemostasis 2. Inflammation 3. Proliferation 4. Maturation. Healing can result in scar tissue because only some parts actually regenerate to its original self. Not all parts of the body heal completely after injury either. In terms of how an injury affects a person physically, mentally, and spiritually, healing can mean bringing these aspects of a person back to where they feel complete.


Too much movement. Being “double-jointed” is one way a person can have hypermobility. It also can happen after a ligament sprain. Ligaments hold bones together and when injured they don’t have the bones as tight as it did before. Excessive movement in a joint can cause muscles to tighten up more so it can hold position well enough to move functionally. 


No enough movement. This can happen from lack of movement, an injury, or from a specific condition. This can also be referred to as stiffness.


This is the second stage of healing. When there is an damage to part of the body, the body responds with inflammation. The signs of inflammation include redness, heat, swelling, and pain. Those signs appear because inflammation brings in more blood to the area and natural chemicals helps to healing process. 

Isometric Contraction

Activating a muscles with resistance where the body holds a static position. The force can be increase or decrease during isometric contractions.

Isotonic Contraction

Activating a muscle with a resistance that consistently stays the same during movement. This is what happens when lifting dumbbells.

Jacked Up

Not so much a medical term, but it has become a new word to describe a problem many clients develop. Jacked Up refers to the presence of a collection of muscles that are in spasm or adhesions. It will also cause the surrounding joints to be stiff. To the touch, muscles that are Jacked Up will feel hard, dense, and be painful. 

Joint Mobility

Joints are where the end of two or more bones come together. In order for a joint to allow range of motion, it has to be able to move on a smaller level. This are called accessory motions. Joint surfaces slide back and forth, in and out, up and down, and rotate. When these smaller movement are combined together, we achieve range of motion. 


Strong fibrous connective tissue that holds two ends of bones together to form a joint. All synovial joints have ligaments holding them together. Think of these like strong ropes tied to the bones.


Blood vessels have fluid flowing in a certain direction that circulates through the highway of tubes. The tiny vessels that allow fluid movement in and out of organs or tissues is through micro-circulation. This happens in the capillaries. When there is an injury, these smaller vessels need to be stimulated to deliver oxygen and nutrients in and carry carbon dioxide and other by products of the injury out.


In general terms, mobility refers to the movement of the whole body. We can say you have good mobility if it’s easy to move around. Likewise, poor mobility can be described as having a harder time moving around.


These are made up of connective tissue in the body that has contractile elements that are responsible for movement and stability of the joints. Muscles are made up protein bundles encased in larger bundles of protein strands wrapped up in more connective tissue called fascia. The function of a muscle is often compared to a “rubber band” because of its elastic properties. Nerves connective to junction points in muscles to send and receive messages from the brain. Tendons connect muscles to bones.

Muscle Memory

When a muscle is used a certain way to complete an action, a part of the brain communicates through a pathway with the muscle. It created a record of it in the brain and along the path making it easier to recall the next time it’s performed. So, the more an action is completed, the more familiar your body becomes with what you are trying to do. You can build muscle memory by practicing an action over and over again. Some say muscle memory takes 5,000 to 10,000 repetitions to take effect.


Nerves are literally the power cord from our brain to the organs of the body. The send and receive messages through electrical and chemical transmission. Just like extension cords, most nerves are made up of bundles of fibers encased in an outer covering called a myelin sheath. Its a fatty substance the boost the speed of transmission of nerve impulse . These connect the brain, spinal cord and receptors throughout the body.

Some nerves in the body are not insulated which means they are slower to communicate their message back to the brain. Unlike myelinated nerve fibers, unmyelinated nerves can have their message to the brain interrupted during transmission. This is the case of Type C nerve fibers which are responsible for telling us we are in pain or other sensory information like itchiness.


These are tiny dots that look like bruises when tiny blood vessels called capillaries release blood to the surface. This is common after Instrument Assisted Soft Tissue Mobilization or Myofascial Cupping. It happens because scar tissue and adhesions bind to the capillaries and become separated. It is a sign that a new healing response was created. Capillaries will find new pathways if they are disturbed. 

Range Of Motion

Also labeled as ROM, range of motion is a standardized way to describe movement. Each muscle and joint has only so much movement. ROM occurs in different directions which also have specific names so it is easier to identify which way its being moved. Because the body has parts that hold itself together, ROM only goes so far before structures become injured.

Scar Tissue

A normal build up of protein in the form of collagen. The fibers cross over each other like matted fur on a pet or thatch on a grassy lawn. This happens after an injury. It can hold back movement if the scar tissue doesn’t align in the proper direction.


These are involuntary muscle contractions that engage the whole muscle. Sometimes these are referred to as cramps and Charlie horses. Muscle spasms happen for different reasons. For example, a muscle will go into spasm if the muscle is trying to protect itself from an injury. They can also happen if the body doesn’t have a proper balance of water, sodium, and potassium.


An injury when there is a partial tear the end of the ligament or a completed detached. Sprains leave a person with difficulty holding the connecting bones together. And you lose valuable feedback to the brain about where that injured joint is in actual space relative to its surroundings. Plus, muscles that support a sprained joint will be slower to react to movement and stability.


When a joint can maintain proper position during an action, it is thought to have stability. A lack of stability would look like an inability to maintain a position during an action. When we move our arm overhead, the shoulder joint stabilizes itself with muscle contractions. Otherwise, the joint could move out of position and the movement could not be completed.


An injury that occurs when enough stress is placed on muscles, tendons and fascia that causes the tissue to break. This can range from a little (micro-trauma) to a lot (massive tearing). The more strain on the body the more inflammation will be created to repair.


Strength can be explained in 2 basic ways. First, it is the amount of force that can be created by a muscle in a single effort. Keep in mind, the ability to hold a solid muscle contraction also requires the support of other parts. Second, strength is measured by a specific task. This is referred to as functional strength. An example of functional strength carrying a box. Sometimes a person can have good strength on muscle testing, but not enough to perform a specific task. This is related to the Principle of Specificity. 


The opposite of a contraction is stretching. Muscles that lengthen are being stretched. Stretching is an example of a Therapeutic Exercise.

Synovial Fluid

This non-Newtonian fluid can be found inside most joints of the body. It provides lubrication, nourishment, and shock absorption to the joints.


Strong connective tissue that attaches muscles to bones. Tendons are denser than muscle and have few contractile elements. They are also have an outer casing called a tendon sheath which is usually the part affected with tendinitis.


Inflammation of tendons, especially in the sheath. Tendinitis can happen when there is too much rubbing of the tendon cord inside the outer sheath, direct trauma, contracting a too strongly, or overstretching a muscle causing a strain.

Thixotropic Effect

This is a phenomenon that occurs within the tissues of the body. When shear forces are applied to the tissues, the fluids within the cells become thinner by reducing the friction of the molecules. In other words, the tissue becomes lubricated.

Trigger Points

Trigger points are mini-muscle spasms. Rather than the entire muscle cramping up, only part of the muscle tightens into a knot. You know you have a muscle knot when you can feel a hard, dense nodule in the muscle that hurts if your press on it enough.

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