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.