Knee Arthritis, good to run, bad to run?

One of the most common statements we runners hear is that running causes knee damage and, “You will wear out your joints!”  This statement comes from not only our friends and family but our trusted health care providers.  A 2018 study interviewed health care practitioners (HCP) and the general public about whether they felt running caused knee osteoarthritis. Both groups showed a high degree of negative perceptions about the relationship between running and arthritis. Of particular interest, between 17 to 30% of doctors, PTs, chiropractors and athletic trainers think long distance running increases knee arthritis risk.

There is not a lot of evidence to show that running either causes or makes arthritis worse. In fact, a recent study found that runners have less knee pain than others and less chance of knee arthritis.  In . “The Association of Recreational and Competitive Running with Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis” Journal of Orthopaedic & Sports Physical Therapy 2017, the authors completed a systematic review  of 25 previously published papers encompassing more than 125,000 individuals revealed that the overall prevalence of hip and knee OA is 10.2% in non-runners and only  3.5% in “recreational” runners who were defined as everyone except professional, elite or ex-elite runner/athletes.

So for the most of us, the recreational runners, we develop knee arthritis at 1/3 the frequency of people who do not exercise!

Osteoarthritis of the knees has been linked to heredity, obesity, and joint trauma. If your parents, grandparents, uncles, aunts, brothers, or sisters have had knee arthritis, there is a good chance you will, too. If you have a BMI over 30, you are at risk.

Even in the presence of  many of these factors, which are beyond our control, those who run still may experience less pain in the presence of knee arthritis as compared to those who do not.  One place where running can significantly decrease the risk of developing arthritis and pain is with weight loss.  Ten pounds of extra weight in the trunk is like 30 pounds through the low back, 50 pounds through the hips, and 70 pounds on the knee joints.  In a prior study an increase in BMI of only two points can increase the risk of knee arthritis by 36%, so running in conjunction with a sensible eating plan will go a long way to diminishing this risk factor.

You can’t pick your family history, age, or your born gender, but addressing undesired weight gain, optimizing squat and movement mechanics and thoughtful rehabilitation of knee injuries are all factors that can be improved.  I have found working with many runners, injured and not injured that a large proportion have a significant decreased ability to extend and push the hip behind the body and use the glutes as a main driver of running.   This comes from the prevalence in our society of sitting and activities that results in short and tight hip flexors and inactive glutes.  As a consequence, to run further and faster, we arch our back to extend the hips, use our quads even more to pull the leg forward and land with our feet well forwards of our center of gravity, resulting in even greater forces applied over the knee.  As the patella is basically a pulley for the quads muscle, as we load the muscle more and more compressive force is applied to the knee cap driving it into the femur which increases sheering.  An inevitable outcome is patellofemoral pain syndrome aka runners knee, and when sheering forces occur over time, the mechanical and chemical changes that occur may be the precursor for the development of knee osteoarthritis.

As runners we can begin today with a progressive regimen of stretching the hip flexors, activating and strengthening the glutes and completing drills outside of our runs to groove movements that enhance hip extension and glute activation specific to our running gait.