Teeterboard

The teeterboard (or Korean plank) is an acrobatic apparatus that resembles a playground seesaw. The board is divided in the middle by a fulcrum made of welded steel. At each end of the board is a square padded area, where a performer stands on an incline before being catapulted into the air. The well-trained flyer performs various aerial somersaults, landing on padded mats, a human pyramid, a specialized landing chair, stilts, or even a Russian bar. Source : https://en.wikipedia.org/wiki/Teeterboard