Owning a skill is not an easy thing. I taught skiing at Whitetail and once had a clinic with an instructor named Mark Goodman and he told me that practice does not make perfect, perfect practice does. The thing about yoga with a class is that you get the corrective feedback from the instructor and the energy from practicing with a group. I had trouble with standing tall and Mark used a bamboo stick to give me the feedback where I was standing by pacing it underneath the back of my jacket. That was an excellent self discovery exercise but to really own that posture I had to go to yoga practice to unwind and develop the core and back muscles to stand tall which gives you more leverage skiing. To really improve once a week does not cut it- particularly if you are not that naturally flexible like me. You can supplement the classes with your own practice a few times a week . It is also a great way to relax and yoga masters don't make it to 100 years by accident.