Lindsey Vonn was pushing hard down an Austrian mountain in the opening Super-G race of the 2013 Alpine World Ski Championships.
Vonn's class was not in doubt. In 2010, she had won gold in the downhill and bronze in the super-G at the Vancouver Winter Olympics. The Minnesotan had then gone on to establish herself as one of the greatest ski racers of all time, winning four World Cup championships and more World Cup races than any other American.
But 42 seconds into this run, she was in second place.
Straining to narrow the gap, Vonn approached a jump just after completing a hard left turn. To the untrained eye, she left the snow with no problems and flew, tucked aggressively, through the air.
As she hit the snow, her right leg instantly buckled sideways from underneath her body as her right knee collapsed and twisted. She would eventually come to rest in a fence at the side of the slope.
Unable to move, the racer was airlifted to a nearby hospital to discover she had torn her anterior cruciate ligament and medial collateral ligament in her right knee.