Compliance vs Stiffness

Photo by Brett Sayles on

I geeked out bit this weekend. Saturday I had a bunch of volunteers to do gait analysis. I used my new RunScribe pods to gather some data and help me compare it to my typical running analysis. I could write a whole book on this stuff, but just to pull out some data points and give you a sample.

  1. Stiffness vs. Compliance – Stiff runners run with less overall degrees of movement. They tend to be your heavier, taller, older guys. There is some evidence so show they have higher rates of certain injuries like PF pain. Compliant runners tend to have more bounce and more motion in their knees and hips. These are the runners that look like lab puppies, just legs and hips everywhere. These are the runners I recommend more core work, strengthening work. Observationally you can see this with a high bounce in their pony tail. I would typically mark 5cm and 10cm on a treadmill and based on their trajectory on the video analysis, I could estimate what their bounce or vertical oscillation looks like. With the sacral pod, I was able to clearly see a 12 cm vertical oscillation on one patient and be able to graph it out.
  2. Stiff Runner – Increase cadence. Fast turnover and more steps per minute will help reduce overall joint reaction force. Sometimes I do coach these runners to bounce more, develop more calf strength to get some height to improve their turnover and efficiency.
  3. Compliant runner – Running form, strengthening, hills and sprints. You want to develop their skill as a runner: rhythm, timing and coordination. Loading it up is the best way to do this.

Sunday – I ran the Cherry Blossom 10 miler. I volunteer when I can to be a medical runner. While there were a few runners who stopped and slowed down with some concerns there was nothing like last year where a runner went into cardiac arrest at mile 9. For me, It was a test since my training wasn’t ideal. See – post about sacral fracture. I did it in good time as well!


Published by Dr. Dat Q. Cao

Runner, Physical therapist, Husband, Dad. Loves paddle boarding, traveling, dogs, sushi, BBQ

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