If you’ve ever been to a physical therapist, you know that exercise is usually prescribed as the primary treatment for a number of injuries and conditions. Clearly exercise has numerous benefits, but it can sometimes seem counterintuitive to place resistance or load through an injured area — doesn’t it need time to rest and heal? The short answer to that question is generally yes, especially immediately following the injury; however, the right amount of movement and exercise can actually promote healing and recovery from injury. This is where PT comes in.
My goal is to help you understand just how exercise helps restore normal functioning of injured body tissues. This article is part of a series that will discuss how various types of tissue depend on movement to recover. Today’s subject is cartilage, specifically the type that protects your joints from impact and is implicated in the onset of osteoarthritis. This type of cartilage is called articular cartilage. The scope of this article is how exercise helps a joint that is painful due to age- or activity-related changes, not acute articular cartilage injury due to trauma.
Articular cartilage covers the ends of bones where they connect to each other at joints. For instance, there is cartilage covering the end of your femur and the top of your tibia (shin bone) where they meet to form the knee joint. Over time, a loss of thickness in this tissue is normal and not always associated with pain. However, for many people, particularly those who aren’t very active, the loss of tissue can become painful and inflamed. This is termed osteoarthritis. It may seem counterintuitive that something often referred to as “wear and tear” is most common in people who don’t move very much and thus aren’t exerting much wear or tear on their joints. However, there is a distinct explanation for this phenomenon.
Cartilage receives most of its nourishment from nutrients being diffused or pushed into it from the fluid inside the joint. It does not have a very good blood supply like most of our other tissues. Therefore, it is reliant on movement to provide it with a fresh supply of nutrients; if you don’t move often, it doesn’t have a chance to receive adequate nutrition and degenerative changes can take place. The cushioning ability of the cartilage in terms of thickness and strength depends on frequent movement! Therefore, your PT will often address pain related to osteoarthritis using a graded exercise program.
Look out for the next article in the series about tendons and ligaments.
Written by: Dr. Scott Newberry