Freestyle motocross rider Jeremy Lusk was killed last night after he sustained head injuries during an X-Knights event in Costa Rica. He was performing a move known as the Seatgrab Indian Backflip when he lost control of his bike.
Video of the crash shows Lusk completing the initial trick of his run in San Jose's Saprissa Stadium, but after his launch from a second, smaller ramp, his bike pitched forward while he attempted a landing after a back flip.
His full-face helmet sheared apart on impact with the landing surface and stopped the forward movement of his head as his body flipped over. He had a similar crash in the 2007 X Games but escaped serious injury.