In terms of sport, the use of poles for vaulting distances was recorded in Fierljeppen contests in the Frisian area of Europe, and vaulting for height was seen at gymnastics competitions in Germany in the 1770s. One of the earliest recorded pole vault competitions was in Cumbria, England in 1843. The basic rules and technique of the event originated in the United States. The rules required that athletes do not move their hands along the pole and athletes began clearing the bar with their feet first and twisting so that the stomach faces the bar. Bamboo poles were introduced in the 20th century and a metal box in the runway for planting the pole became standard. Landing mattresses were introduced in the mid-20th century to protect the athletes who were clearing increasingly greater heights.