http://www.stottpilates.com/media/newsletters/2010/201010/index.html#success

This is a good question and answer that STOTT posted in their newsletter.  Many people struggle to maintain neutral and it is okay to imprint the spine.  As you get stronger you will be able to maintain neutral better.  Another reason why practicing is very important.  Its a long weekend for Canadians – HAPPY THANKSGIVING!!!!