rabbit:
(plural: ‘rabbits‘ — for the right pronunciation of this word, please click here)

Ethiopian long distance great, Haile Gebrselassie, running as a rabbit for men’s race at the Virgin Money London Marathon
a person who plays very badly or poorly at a game or sport;
a runner who runs very fast to set a fast pace for another runner of his team in a long-distance running race;
A pacemaker, pace-setter, or rabbit (colloquial) is a runner who leads a middle- or long distance running event for the first section to ensure a fast time and avoid excessive tactical racing. Pacemakers are frequently employed by race organisers for world record attempts with specific instructions for lap times. — https://en.wikipedia.org/wiki/Pacemaker_(running),

Scott Overall, rabbit for Britons attempting to win Olympic selection in Sunday’s Virgin London marathon
My younger brother is a known rabbit; nobody wants him on their team.
Johnson is the rabbit to set fast pace for Rodger who is expected to win a gold medal for our country in the long-distance race event in the coming Olympics.
