premise1: An unfortunate accident occurred at a racetrack, where a horse stumbled and fell to the ground, taking the jockey down as well.
premise2: A horse has fallen down on the green grass and the jockey riding on top is trying his hardest to not fall off.
premise3: A jockey in white is in the middle of being thrown from his horse.
premise4: A jockey braces himself as his horse falls.
premise: An unfortunate accident occurred at a racetrack, where a horse stumbled and fell to the ground, taking the jockey down as well. A horse has fallen down on the green grass and the jockey riding on top is trying his hardest to not fall off. A jockey in white is in the middle of being thrown from his horse. A jockey braces himself as his horse falls.
hypothesis: Rider falling.