premise: A male Equestrian rider leans forward as his horse stretches out for the 2nd jump of the course, as the crowd looks on with amazement. hypothesis: A group of people are sledding down a snowy hill.
contradiction: A single male Equestrian rider is not a group of people but a single person. The rider cannot lean forward as his horse stretches out for the 2nd jump of the course while also sledding down a snowy hill. These actions are not compatible.