Locust Hand position

I learned locust pose with the palms facing up so the palms or fists are between the legs and the hips at the joint. Some teachers, especially more recently have the palms flat on the ground. I don't think either position is right or wrong but just different. I do find that I have a much harder time with the palms facing down flat because my arms and especially my elbows do not want to twist in that position. Is there a good exercise or position for entering that position? Thanks