In 2005, The Guinness Book of World Records listed Barbara Blackburn as the fastest English language typist in the world. This category has since been deleted. For her record breaking feat, she used a mechanical typewriter that used the Dvorak Simplified Keyboard. She maintained 150 wpm for 50 minutes, and 170 wpm for shorter periods. She was clocked at a peak speed of 212 wpm.. The mechanical workings of typewriters were a limiting factor in typing speeds. On modern keyboards connected to computers it is not uncommon to find sprint typists in competitions achieving speeds of more than 270 wpm.