Weak Muscles May Cause 'Runner's Knee'

Hamstrings, quadriceps and fallen arches take the blame in new study

We see a fair amount of knee pain at RPT.  Most of it does well.  New research point to what we've known for a long time.

A new study in the American Journal of Sports Medicine cites that weak muscles may be the cause of the painful and debilitating condition known as "runner's knee".  We call it anterior knee pain or patello-femoral pain sydrome.

People who develop the condition tend to have weaker quads and hamstrings, and as a result, they don't bend their knees as much when doing tasks, such as running or jumping. That means the contact area between the kneecap and the femur is smaller, so pressure is focused and pinpointed on a smaller area.

That, in turn, leads to runner's knee, also known as patellofemoral pain syndrome, said an associate professor of exercise and sport science at the University of North Carolina at Chapel Hill. Runner's knee, which affects an estimated one in four people who are physically active, can lead to osteoarthritis.

The research appears to be the first of its kind to study athletes both before and after they develop runner's knee, according to the study's author.

The researchers studied nearly 1,600 midshipmen from the U.S. Naval Academy. Of those, 40 people -- 24 women and 16 men -- developed runner's knee over several years.

The study authors noted that those with weaker hamstring and quadriceps muscles, a larger "navicular drop" (flattening of arches in the foot) and less flexible knees were several times more likely to develop the condition.

This condition is amenable to physical therapy and we strongly recommend that people get therapy quickly before their knee degrades, and it becomes too late.