I've tried out the locust pose today and it really feels better than the sphinx pose. I could only hold it briefly (though slightly better than superman with the arms in front), not quite twenty seconds before collapsing, and I didn't get up very far, but it didn't feel uncomfortable in my lower back like sphinx, just hard to hold. So thanks for pointing me to these. Maybe over time my back will get stronger and better with movement in that direction as well.