This has been my most requested video for over a year. The scrub is a technique that allows you to stay lower to the ground and therefore make a shorter trajectory on a jump to go faster. You are less likely to overshoot and as a result do not have to brake as much coming onto a jump. Every downhill athlete uses that technique to win races, but it's also a very good skill to have for any advanced rider sending it in the bike parks.
Photo courtesy by Matthew Tongue
Video by Alexander Chapellier