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11.6 Inflammation

Inflammation is the body’s natural way of protecting and healing itself when injury or infection is present. While helpful in some situations by responding to damage and sending immune cells to help address a given problem, inflammation can also result in difficulties moving.

The 4 key signs of inflammation: pain, warmth, redness, and swelling.
“The four cardinal signs of inflammation” by Koen Liddard, CC BY-NC-SA 4.0

If you have ever injured yourself, you may have noticed the injured area becoming red, swollen or enlarged, warm, and painful; these can all be signs of inflammation! As a result, the area or joint may have been hard to move through its full range of motion or at least was uncomfortable in doing so.

Generally, inflammation is a good sign and lets you know that the body is responding to an infection or injury. It does so by sending molecules to the area of concern to help do one of four things.

  1. Defend against foreign and potentially harmful agents such as bacteria or viruses.
  2. Prevents further injury by discouraging use of the area through pain, swelling, or both.
  3. Promotes healing and repair by delivering Immune cells through increased blood flow
  4. Removes unwanted or damaged cells from the area to make room for healthy cells and new growth.

However, some conditions are characterized by inflammation either globally throughout the body or locally within a specific body part or area. Although these conditions have various names, one commonality they have is their use of the suffix “-itis”. Knowing that “-itis” refers to inflammation, it becomes easy to identify conditions which describe inflammation in different parts of the body. Consider the following examples:

Bursitis

A condition describing inflammation of one or multiple bursae, a fluid-filled sac found throughout the body, which acts as a cushion between bones and soft tissues.

  • Athletes who rely on overhead shoulder movement may experience subacromial bursitis, bursitis of the bursa that sits approximately above the shoulder joint and below the clavicle or collarbone (left image below).
  • Athletes who flex and extend their elbows frequently during physical activity may experience Olecranon bursitis.
See caption.
Side-by-side photos of two athletes: on the left, a swimmer performing a freestyle stroke in a pool; on the right, a tennis player preparing to serve on a clay court, gripping a racquet and holding a tennis ball. “Swimming” (left) by Emily Rose, Pexels License,Tennis” (right) by Gonzalo Facello, Pexels License

Tendinitis

A condition describing inflammation or irritation of a tendon, often caused by repetitive movements or overuse. A common type of tendinitis is “Tennis Elbow” where the tendons on the outside of the elbow are affected, or “Golfers Elbow,” where the tendon on he inside of the elbow is affected

Plantar Fasciitis

A condition describing inflammation of the plantar fascia, a thick band of connective tissue that runs along the bottom of the foot. A common cause of plantar fasciitis is high-impact activities such as running.

Arthritis

A general term for inflammation of the joint resulting in pain, reduced mobility, and swelling. While there are several types of arthritis, two commonly known types are osteoarthritis and rheumatoid arthritis.

Osteoarthritis

A condition associated with advanced age or overuse that has known ties to long-term inflammation. Osteoarthritis is caused by the wearing away of the joint cartilage that is supposed to cushion the joints, but is no longer able to.

Rheumatoid Arthritis

An autoimmune disorder that impacts one or more joints. With rheumatoid arthritis, the body sees its own joint lining as a threat, causing an inflammatory response.

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The Foundations of Human Movement and Physical Fitness Copyright © 2025 by A.J. Stephen; Sarah Fraser; and Connor Dalton is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.