In the 4x100m Relay each athlete covers one 100m leg of the track, whereas in the 4x400m Relay each athlete covers one complete lap of the track.
In the Class T11-13 relay (visually impaired athletes) and the T35-38 relay (athletes with cerebral palsy), the runners must race with a baton in their hand, passing it on to the next athlete in their team until the final athlete crosses the finishing line. The baton is a smooth hollow tube, 28-30cm long and about four centimetres wide.
In wheelchair and amputee relays, the changeover is achieved by the incoming athlete touching the body of the outgoing athlete, which needs to happen within the changeover zone.
The changeover is the crucial point in the relay race. Athletes have a 20m zone in which to pass the baton, or touch the next athlete – the key is for both athletes to be travelling at speed while passing the baton within the zone.
In races where athletes run with guide runners, both athlete and guide must be within the zone when the changeover is made, although either can carry the baton.
The number of heats and rounds depends on the number of athletes competing, but there will not be more than three rounds – heat, semi-final, final – in any event.
The draw to determine which heat a team will run in is decided by their initial seedings (based on previous performance) for the first round, and then their performances after that, ensuring that the highest seeded teams are not allocated the same heat.
Keys to success
Both the 4 x 100m and 4 x 400m races are sprints, and so a good start for the first athlete is vital. However, the winning teams will be the ones who can also make their changeover in the most efficient manner – with both athletes maintaining as near to top speed as possible.
Breaking the rules
While it is not against the rules to drop the baton, crucial time is lost picking it up, and if in doing so an athlete obstructs another team they will be disqualified.
For more information, please go to the International Paralympic Committee (IPC) website.
Read more about classifications in Paralympic Athletics