The purpose of yoga isn't the strength to balance on your forearms or the flexibility to arc your leg upward until your toes touch the crown of your head. The physical acrobatics are just a fancy way to get the mind to calm down and give the body permission to do nothing but breathe. So Sarah Kucera has it pretty easy. Her warm, authentic demeanor seems to melt the stress from her students when she greets them at the sign-in sheet. That's not to say this popular instructor at Kansas Siddhi Yoga is all talk. Her graceful demonstrations of difficult postures could lead even the most enlightened to feel jealous. Her flowing sequences give away her primary profession as a chiropractor who understands the intricacies of human anatomy. But in this age of yoga DVDs and fancy alliance certifications, Kucera isn't clinical or pretentious. She's able to read the room and tailor each class to the students' energy levels — whether a challenging pace or something a bit more indulgent. Whereas many instructors teach their classes in the hushed cadence of a dog trainer in a library, Kucera sounds like a friend, chatting brightly over a cup of coffee. What better way to relax?