Everyone has exercises for which they are anatomically designed to perform well, and exercises which simply will not be possible to do without a serious potential for injury due to anatomical limitations. It's aggravating- most people who work out with Cathe are dedicated to working out seriously, and we quite naturally want to be able to do it all, and do it all well. I believe we do need to at least try each exercise. Most exercises can be mastered through the magic of the brain and muscle memory and sheer hard-won strength. But if after a certain amount of time it feels painful, wrong, or dangerous, I personally stop the movement immediately. Sometimes we can get by with just modifying an exercise, but other times we need to omit the movement entirely. Many of us (count me in!) learn this the hard way, typically through injury, sometimes one that's long-lasting and expensive to treat.