This is an excellent physical warm-up (and cool-down) that I recommend to students and teachers alike. Go to www.bapam.org.uk and click on factsheets at the top of the page. It only takes about 10mins to do and is an absolute must for all levels and ages. Can prevent all sorts of muscular problems in musicians, if done on a regular basis. Remember to take regular breaks from practice. I do no more than 30mins practice before having a quick cuppa!