The diving maneuver known as the JACKKNIFE involves a diver entering the water feet first with their arms and legs tucked in close to their body, creating an angle of 90 degrees or more. The PIKE is a similar maneuver, but instead of entering the water feet first, the diver enters head first with their arms and legs extended straight out. Both of these maneuvers are used by divers to increase speed and reduce splash when entering the water.