Mr Kieser I have a personal training studio in the USA. I have several pieces of MedX and Nautilus. The more I learn of the Kieser system the more I have adapted the exercise principles. Having been involved intraining for 45 years I have been a student of exercise for most of my life. I believe the principles and information presented in your your writings to be the very best and most relevant to date. I am converting from solely compound movements to a mix of compound and isolation movements. Besides compound exercise I have B1,B7 I am currently considering a trade - a C7 for an E2 . I have C1 and C3 ,and J2. My question is do you think the C7 is essential or do the other back exercises cover other muscles, specifically the rhomboids? Please excuse any translation difficulties. Thank you for all the work you have done and what you continue to do Dennis