Open Access. The published version of this work has been reproduced here with permission. This article may be downloaded for personal use only. Permission to reproduce this article must be sought from the Singapore Physiotherapy Association. This article was first published in Physiotherapy Singapore, 4(4): 15-22, 2001. More information about this journal may be found at http://www.physiotherapy.org.sg/PTJournal.aspx. Copyright (2001) Singapore Physiotherapy Association.