Rolf \ˈrȯlf\ Ida P. (1896–1979), American biochemist and physiotherapist. Rolf received a doctorate in biochemistry and physiology. After working 12 years as a biochemist, she devoted 40 years to developing a new kind of physical therapy involving vigorous manipulation of the body's underlying musculature. The muscular manipulation was held to correct the body's structure so that it would be in alignment with the earth's gravitational field. Rolfing became an object of considerable popular interest in the 1970s.