The Cheat Sheet to Naming Body Movements

We’ve all probably heard the old joke “Doc, it hurts when I do this.” And then the punchline, “Don't do that then.” If you’re searching online trying to figure out what hurts, knowing some of the movement terms can help.

The human body only moves in so many ways, due to the way joints, muscles, and other tissues are arranged. Once you know what those ways are called, it can help you understand the structure too. Why your shoulder keeps getting cranky, what your trainer actually means when they say "hinge at the hip", and why stretching or strengthening one muscle can fix a problem somewhere else.

Actions are typically described in pairs, usually the opposite of each other. The nervous system is significantly involved to coordinate both the main action muscle groups (agonists) and those that do the opposite (antagonists). This relationship forms the basis for some of the different stretching methods, such as proprioceptive neuromuscular facilitation (PNF).

The terms are related to what’s called the anatomical position, which is standing tall, arms at your sides, palms facing forward. Sounds picky, but you need a consistent starting point.

Flexion and Extension

Flexion decreases the angle between two bones. Curling your arm to show off your bicep? That’s flexion at the elbow. Bringing your knee up toward your chest? Flexion at both the hip and knee. Extension is the opposite, it opens the joint back up increasing the angle between two bones. Straightening your arm back out is elbow extension. Standing back up from a squat is hip and knee extension. Because of the way they are referenced, bringing your upper arm or upper leg backwards is also considered extension of the shoulder or hip.

A few areas where the terminology gets a little weird are the foot and wrist. Pointing your toes downward (like you're pressing a gas pedal) is called plantar flexion. Pulling them back up toward your shin is dorsiflexion. The names are different because the foot operates on a different axis of movement than the rest of your leg, ankles are just special like that. The wrist is very similar, but instead of plantar flexion it’s called palmar flexion. Bringing the back of your hand towards your forearm is dorsiflexion.

One other variation is the spine that can also have lateral flexion, which is a bend or lean to the left or right. Think of tipping your ear toward your shoulder or a side bend for your low back. Either or both of the Quadratus Lumborum (QL) muscles tightening up along the sides of your low back are responsible for a significant amount of low back pain.

And yes, hyperextension is a real term, it just means going past the neutral position. Leaning too far backward for the lower back, or straightening your elbow a little too much, can cause pain and damage to the joints and surrounding tissues.

Abduction and Adduction

Here's a pair people always mix up. Think about making a snow angel, arms and legs away from your body, then all back towards. Abduction moves a limb away from the middle of your body. Raise your arm straight out to the side, that's shoulder abduction. Spread your fingers apart, finger abduction (the midline shifts to your middle finger for the hand, which feels arbitrary, but again the reference point used). Adduction is just bringing it back. Lowering your arm back down or bringing your knees together. 

The trick a lot of people use is abduction sounds like "abduct," like kidnapping the limb away from the body. Adduction "adds" it back. Sounds a little cheesy, but it works. I still teach it this way.

Here's why this actually matters besides on a vocab quiz: every time you take a step and balance on one foot for a split second, your hip abductors (mainly a muscle called the gluteus medius) are working hard to stop your pelvis from tipping to the side. When that muscle is weak or lazy, the compensation you have to do spreads up and down the chain. Bad hip abductor strength (that can happen from prolonged sitting, making glutes stretched and weak) is quietly responsible for a surprising amount of knee pain, IT (iliotibial) band problems, and chronic low back pain. A single underperforming muscle group, causing chaos everywhere but where it actually is.

The shoulder has another set of movements called horizontal abduction and adduction. Similar principle, but start with your arms straight out in front of you. Moving your arm parallel to the ground out to the side is horizontal abduction and bringing it back towards or across your body is horizontal adduction.

Rotation, Spin, and Circumduction

Not every joint rotates, but shoulders and hips do a lot of it. Medial (internal) rotation turns the limb inward, toward the center of your body. Lateral (external) rotation turns it out. When a baseball pitcher winds up and holding to throw, the shoulder is cranked into serious external rotation. The actual throw is a burst of internal rotation. Get that sequence out of whack and you've got a rotator cuff problem waiting to happen. 

It can be easier to visualize rotation in the shoulder by bending your elbow like you’re holding a cup. Bring the cup towards your chest just rotating your shoulder, that’s internal rotation. Rotate the cup out away from your body, that’s external rotation. This is similar in the hip: bend your knee and try to rotate your knee towards your other knee, internal rotation. Rotate your knee away from your body, external rotation.

For the spine, we typically refer to any rotation as either left or right rotation. Turning your head to look over your shoulder is an example, but you can also have rotation in your upper and lower back. Having a decreased range of motion in your upper back (thoracic spine) can cause other areas to compensate leading to neck or low back stiffness and pain.

The forearm has a unique, separate joint at the elbow that allows one bone to spin around the other, think turning a doorknob or working with a jar lid. Depending on whether your elbow is bent or straight, supination is turning your forearm palm up or forward. Pronation is turning your palm down or backward. When we mentioned anatomical position earlier, part of the description was to have the palms forward (supinated). Repetitive overuse of some of the muscles that do these actions can lead to tendon inflammation and carpal tunnel symptoms.

Circumduction (think circle motion) is more a combination of all several of the others done in sequence. Swing your arm in a big circle, like you're warming up and that’s circumduction. Your joint is cycling through flexion, abduction, extension, and adduction in one smooth loop. The joint isn't actually spinning on its axis, it's sweeping through a cone of space. Rolling your ankle around before a run? Same thing.

It’s Complicated: The Shoulder Blade

The scapula (your shoulder blade) is honestly kind of wild. Most bones in the body are locked into rigid joints. The scapula just... glides around on the back of your ribcage, held mostly in place by muscles. That's what lets your arm reach overhead, scratch your back, and throw things. All that mobility comes at a cost, though. The muscles controlling the scapula have to be doing their jobs constantly or the whole shoulder system starts breaking down.

Actions the scapula can perform include elevation, depression, protraction, retraction, rotation both upward and downward, and tilt both anterior (forward) and posterior (backward). If it's sitting wrong, every arm movement gets altered. 

Most shoulder impingement problems can get traced back to this. Upward rotation is one that can cause the most trouble when it goes wrong. As your arm lifts from your side toward, your shoulder blade is supposed to rotate upward at the same time, roughly two degrees of arm movement for every one degree of blade rotation (called the scapulohumeral rhythm). When that timing gets disrupted, the bony roof of your shoulder starts pinching the soft tissue below it when you raise your arm, called impingement.

Why Any of This Matters

You don't need to memorize all of this, but being familiar does change how you interact with your body. If a trainer cues you to retract your shoulder blades (scapulae) before a bench press, you can feel what that means instead of just guessing. If your knee hurts after running, you can start wondering whether the problem is actually your hip mechanics. Because now you know that hip abduction is a thing, and it can affect how load travels through your knee.

The body is a chain, not a collection of isolated parts. Pain shows up in one place, but the cause can live somewhere else. Getting better in movement vocabulary helps to get better at reading the chain. Once you can you can describe what you’re doing when something hurts, you're already halfway to fixing it.