"Mr. Iyengar’s practice is characterized by long asanas, or postures, that require extraordinary will and discipline. A reporter who watched daily practice in 2002, when Mr. Iyengar was 83, said that he held one headstand for six minutes, swiveling his legs to the right and the left, and that when he finished, "his shoulder-length hair was awry, he seemed physically depleted," but he wore the smile of a gleeful child."