Yoga

woman doing the 'downward dog' posture, but her lower back is rounding to compensate for lack of hamstring flexibility

woman engaging in bent-knee hip flexion while maintaining a neutral spine in a proper squat posture, likely because she does yoga poses like downward dog to stretch the hamstrings.

Yoga postures are sometimes practiced by incels to calm their depression.

A lot of women also do it for fitness or to look sexy.