sentence: We see a BMX biker as he prepares to to ride. sentence:  We see the gate open and see the field. sentence:  The rider takes off down the course. sentence:  We see riders perform jumps and people riding bikes. sentence:  We see another start and a group of people take off in an indoor track. sentence:  We see shots of men riding outdoors and another gate opens. sentence:  We see a bike laying on it's side.