Osteoarthritis (OA) is the most common form of arthritis, affecting millions of people worldwide. It is a degenerative joint disease in which the smooth cartilage that cushions the ends of bones gradually wears away. Without this protective layer, bones rub against one another during movement — leading to pain, stiffness, and progressively limited joint motion. (1-6)
What Causes Stiffness and Loss of Mobility?
Cartilage has two important jobs: shock absorption and low-friction movement within a joint. In OA, cartilage degeneration occurs over years due to aging, repetitive stress, injury, inflammation, or genetic factors. As cartilage thins and deteriorates:
- Bone-on-bone contact increases. Without smooth cartilage, joint surfaces grind against each other, stimulating pain and swelling. (1-6)
- Inflammatory changes develop. Although OA is not classically an inflammatory arthritis like rheumatoid arthritis, low-grade inflammation of the joint lining (synovium) can occur, contributing to stiffness.
- Joint shape and mechanics change. Bones may develop spurs (osteophytes) and surrounding muscles may weaken, reducing range of motion and stability
These changes result in one of the hallmark symptoms of OA: joint stiffness, especially after periods of rest or inactivity. For many people, stiffness is most noticeable in the morning or after sitting, and often eases once the joint is gently moved.
Why Movement Helps
While it might seem counterintuitive, not moving a stiff joint tends to make stiffness worse. Here’s why:
- Joint lubrication improves: Movement stimulates the flow of synovial fluid, the natural lubricant within joints. Better lubrication reduces friction and makes movement smoother and less painful. (7) )
- Muscles stay strong: Strong muscles support and stabilize joints. Weak muscles—common when joints are protected through inactivity—can increase joint strain, worsen pain, and promote stiffness.
- Flexibility and range of motion are preserved: Regular gentle movement helps maintain the ability to bend, extend, and rotate a joint, delaying the stiffness and motion loss that characterize OA progression. (1-6)
Importantly, moving doesn’t have to be intense. Activities such as walking, swimming, gentle stretching, balance exercises, and strengthening routines can all help keep joints moving without overloading them.
Medical Evidence: Movement Is Key
A strong body of research confirms that movement and exercise are among the most effective non-drug treatments for osteoarthritis. For example, a 2023 Cochrane review of multiple clinical studies found that exercise probably results in improvements in physical function and pain in people with knee osteoarthritis when compared with usual care or no exercise. The evidence showed that those who participated in exercise programs had significant improvements in joint mobility and function, supporting the idea that activity is essential for symptom management. (8)
Takeaway
Osteoarthritis causes joint stiffness and loss of mobility through cartilage breakdown, inflammation, and changes in joint mechanics. While rest may be tempting when joints hurt, regular movement is one of the most powerful tools for reducing stiffness, maintaining range of motion, and improving daily function. Guided movement—tailored to individual ability and comfort—can help you stay active, mobile, and engaged in life despite osteoarthritis.
- Bortoluzzi A, Furini F, Scirè CA. Osteoarthritis and its management – Epidemiology, nutritional aspects and environmental factors (https://pubmed.ncbi.nlm.nih.gov/30213694/). Autoimmun Rev. 2018 Nov;17(11):1097-1104. Accessed 10/2/2023.
- Donahue SW. Krogh’s principle for musculoskeletal physiology and pathology(https://pubmed.ncbi.nlm.nih.gov/30179205/). J Musculoskelet Neuronal Interact. 2018 Sep 1;18(3):284-291. Accessed 10/2/2023.
- Hochberg MC, Altman RD, April KT, Benkhalti M, et al.; American College of Rheumatology. American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee(https://pubmed.ncbi.nlm.nih.gov/22563589/). Arthritis Care Res (Hoboken). 2012 Apr;64(4):465-74. Accessed 10/2/2023.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (U.S.). Osteoarthritis(https://www.niams.nih.gov/health-topics/osteoarthritis#tab-overviw). Accessed 10/2/2023.
- National Library of Medicine (U.S.). Osteoarthritis (https://medlineplus.gov/osteoarthritis.html). Accessed 10/2/2023.
- Sen R, Hurley JA. Osteoarthritis (https://pubmed.ncbi.nlm.nih.gov/29493951/). 2022 May 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Accessed 10/2/2023.
