 For sprinting events ( bar the 4 × 400 m relay and the indoor 400 metres ) , each athlete must run the race within their allocated lane from start to finish . If an athlete leaves their lane or steps on the line <unk> each lane the athlete will be disqualified . Lane rules also apply for initial periods of other track races , for example , the beginning of the 800 m . Similar rules apply for longer distance races when a large field of athletes is present and separate starting points are designated , with the field merging into one group shortly after the starting phase . 
