The lengths of the sarcomeres of some muscles of the human leg were determined for the anatomical position, using a method based on diffraction. Measurements were made of the muscle lengths and angles of pennation from cadavers, and these were used to predict sarcomere lengths at other limb positions. The measured and predicted sarcomere lengths were compared with the length-tension curve for human muscle, which showed the range of sarcomere length from both extremes of muscle length to cover the entire range of the length-tension curve.