Using the shin-box/jiu-jitsu position is a great way to assess for hip mobility and core stability, among other things.In this video, you can clearly see that I have way more discomfort on one side where I can’t keep my knee down on the ground.

To address this issue, you can perform hip airplanes where you rotate in one direction from the single-leg deadlift position (I guess you’re supposed to do it with your arms out like an airplane…I normally hold onto something for support when I do these). I worked on external rotation on the side where the knee couldn’t stay down, before I switched legs to work on internal rotation.