Richard J. Johns was born in Pendleton, Oregon. He received his B.S. in 1947 from the University of Oregon and his M.D. in 1948 from the Johns Hopkins University School of Medicine. After serving in the U.S. Army Medical Corps, he returned to Johns Hopkins, where he spent the rest of his career. At Johns Hopkins, he first held positions as instructor, assistant professor, and associate professor in the department of medicine. In 1966, he was appointed the first professor and chairman of the new sub-department of biomedical engineering. In 1970, when biomedical engineering was established as a full department in the university, Johns was named its director and served in that capacity until his retirement in 1991. In this oral history, Johns discusses his history with Johns Hopkins and the School of Medicine and the Department of Biomedical Engineering as well as the general history of both facets of Hopkins. This oral history is part of the Mame Warren oral histories series.

There are 234 muscles in the human body which interpret signals from the nervous system to perform simple and complex operations. Pairs of muscles often work together by expanding and contracting in opposition to each other to perform at optimum efficiency. Muscle contraction consists of physical, chemical, and electrical changes.