A bertslide, Bertlemann slide, or bert, is a skateboarding trick where the skateboarder puts one hand on the ground and rotates the board while it is still on the ground, effectively sliding on the wheels of the skateboard. The trick was named after the surfer Larry Bertlemann, who first performed the trick on a surfboard, then later incorporated it into his skateboarding. The original version of the trick was a 180-degree turn. The Z-Boys, an influential group of mid-1970s skateboarders, adapted the move by extending the slide to 360 or even 540 degrees.