I volunteered to pass out water bottles and snacks at the Silverdale Rotary Turkey Trot on Thanksgiving morning. I have been part of this event for years, both as a runner and a volunteer, and have witnessed the number of participants grow steadily each year. This increase in popularity is nice to see, not only because running is a fantastic exercise, but because it’s also beneficial for our joints.
There is a misconception that running is detrimental to joint health. I have had several people tell me they stopped running, not because it was a pain-generating activity, but because somebody told them that they could end up with hip or knee arthritis as a result.
A recent systematic review has discredited the notion that running increases the risk of arthritis. Titled “The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis,” the study reviewed 17 other articles, which included a total of 114,829 people, and provided great clarity as to whether arthritis is a likely byproduct of running.
The review compared the incidence of hip and knee arthritis in three groups: recreational runners, non-runners and competitive runners. Competitive runners were those who had participated in international competitions. The frequency of knee and hip arthritis in each group was as follows:
•Recreational Runners – 3.5%
•Non-Runners – 10.2%
•Competitive Runners – 13.3%
That data clearly shows that up to a certain point, running has a preventative effect against hip and knee arthritis. While that point is difficult to discern accurately, it’s thought to be a consistent training volume of about 55 miles per week, much higher than most runners.
Why is that? Why would running, an activity that has been shown to increase the impact forces on the hips and knees by several times the body weight, decrease the likelihood of hip and knee arthritis?
The most likely reason has to do with the SAID principle, an acronym that stands for Specific Adaptation to Imposed Demands. The SAID principle means that when the body is placed under some form of stress, it starts to make specific adaptations to the demands you are putting on it. For example, if you do squats, your glutes and quadriceps will get stronger over time.
The SAID principle can also be applied to the weight-bearing joints of runners. As an adaptation to the mechanical stress of running, the cartilage in a runner’s hips and knees is often thicker and more robust than that of a sedentary person. If that loading is applied gradually and does not exceed the body’s capacity to respond positively, tissue remodeling will occur.
While that doesn’t mean that if you run, you won’t get arthritis, it helps to shed light on a controversial topic. It may take years for that information to become more widely accepted, and there will likely come a time when people are taking up recreational running to protect their joints like they currently do with other forms of training.
Dr. Jordan Duncan is from Kitsap County and writes a monthly online health column for the Kitsap News Group. He is the owner of Silverdale Sport & Spine.