Tight sartorius

Fellas, I have an athlete with recurring tightness in her sarorius. It is easy to massage out, difficult to get an effective stretch.

My question is, why is this occurring?

She does run a little duck-toed and has a small inward twist of her foot during the recovery phase - but is this cause or effect?

Any suggestions welcome.

Well is the tightness causing her to run that way or is her running that way causing her to be tight? Have you tried getting her to run right after you get the muscle relaxed/stretched out a bit? See if there is some change in her running after you work on the muscle, this might help you figure it out if you haven’t already tried this.