Why do joints become stiff?

While pain and stiffness often go together, joint stiffness can occur on its own. Joint stiffness can limit your ability to perform usual tasks, such as turning your head to check behind you while driving. Stiffness can also be a warning sign that a part of the body is vulnerable to future injury. There are many different causes of stiffness and below are some of the reasons why you might not be feeling as flexible as normal. 

1. Disuse and lack of movement
Our bodies are designed to move. When we're not regularly moving our joints through their full range, they can begin to feel ‘tight’. This can be caused by a combination of the capsule that surrounds the joint tightening up and the muscles around the joint shortening and losing flexibility. Stiff and tight muscles can cause you to feel as though your joints are stiff, even if it is only the muscle length that is restricting the movement. Joint mobilizations, manipulation and muscle stretches or massage can have a significant effect in improving the symptoms.
The most effective way to maintain full movement is to regularly move joints through their full range, which also helps to keep muscles and joints healthy. Your physiotherapist can advise you on how to best approach this with a targeted set of exercises.
 2. Osteoarthritis (OA)
OA is a degenerative disease, characterized by a breakdown of the joint surface cartilage and the growth of bony osteophytes around areas of stress. While OA is increasingly common as we age, it is thought that the primary cause is abnormal load and stress to joint surfaces and not simply aging itself. As the space between two joint surfaces become uneven, joints affected by OA can feel stiff or even ‘blocked’. 
A person with OA will often feel stiff for around 15-20 minutes after being still. Physiotherapy programs to strengthen the muscles surrounding the joints, to help absorb weight-bearing forces, has been shown to have positive results with OA symptoms. 
 3. Inflammatory Related Stiffness
The inflammatory process is characterized by swelling and pain around a specific area. Usually this is a response to damage by the body. As an area swells, this will allow less space for movement and a sensation of stiffness, as anyone who has had sprained an ankle can attest to. Acute inflammation will cause swelling that increases over 24-48 hours and subsides gradually. Autoimmune disorders can cause the body to mistakenly have an inflammatory reaction where there has been no injury, with resulting pain and stiffness. Rheumatoid arthritis and ankylosing spondylitis are two examples of such disorders. 
Stiffness caused by inflammatory disorders is characterized by a feeling of stiffness after rest, particularly in the morning, that can take longer than 30 minutes to subside. Inflammatory disorders unrelated to injuries are complex in cause and require collaboration with medical teams for best treatment outcomes. Acute injuries are best managed by following RICE protocols (Rest, Ice, Compression, Elevation).