I have a new client who needs to avoid hip flexion exercises because of low cartilage. (She is young and otherwise fit.) I’m trying to compile a list of lower-body exercises. She’s allowed to do body-weight squats. She’s not allowed to do lunges or anything that brings her hip up more than 90 degrees. I’d imagine things like reverse hypers or hamstring curls or bridges are okay. What about romanian deadlifts? Hip thrusts?
I’m seeking to understand her limitations. No more than 90 degree flexion at hip? Any limitations at the knee? Is she limited in the frontal and transverse plane as well? Is she only allowed to lift her own bodyweight, or is that limitation solely with squats?
If she’s not limited in the frontal plane, you have options for adduction and abduction.
If she’s not limited in the transverse plane, you have options for external rotation in squats, i.e. plies.
Another good sagittal plane exercise, if she can do seated exercises, are seated knee extensions, perhaps with a band for resistance or small ankle weights. In that case, her hip would be at 90 degrees but the load is on the knee, not the hip flexor.