Why is WR for 4x100m relay less than 4 times WR for 100m sprint.

  1. Hello,

    The 2012 London Olympics concluded a day or two ago. We saw that a few records were broken in athletics. In particular, the 4x100m men's relay record.

    Currently the WR are as follows :-

    1) 100m Men's sprint - 9.58 s
    2) 200m Men's sprint - 19.19s
    3) 4x100m Men's relay - 36.84s

    The world's fastest man Usain Bolt features in all the races. Thus in the relay the 4 athletes are either as fast as Bolt(i.e Bolt himself) or slower.
    Now if one observes the record time for relay, it is 36.84s , which is less than 4 times the 100m sprint record. Whereas the record time for 200m is more than twice the 100m sprint record.

    I think I understand why it is so for 200m sprint (it is relatively easier to sustain high speeds for smaller bursts ) . But I am unable to explain the 4x100m relay case in a succinct way.

    Each athlete runs 100m in the 4x100m sprint. But only the first runner has to start at the sound of gun fire. Whereas for the other 3 runners, there is a 20m changeover box,during which the baton changes hands. So I guess, the acceleration time and deceleration time for 1st and 2nd runner overlap partially (similarly for 2nd and 3rd , etc).

    I guess my explanation has loopholes and would like to know more about this issue.
  2. jcsd
  3. Filip Larsen

    Filip Larsen 996
    Gold Member

    Since the total time does not include the acceleration of the 3 last runners (the baton gets a "running start" with those runners, so to speak) it is not surprising that the total time is less than 4 x 100m. Even assuming that runners cannot run at their maximum speed when they pass the baton there will be much time saved. For the 400 m relay to compare to 4 x 100 m the next runner would have to wait in his start block and only start accelerating when the baton is in his hand - then you'd see total times >= 4 x 100 m.
  4. Thanks. That was nicely put.
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