i have a friend who failed his 2.4km run but he trained and in
the end clocked 8mins and 20secs below... he told me that he
trained with leg weights while running and in the process of
running he will try to hold his breath for a few seconds then
release then hold again and release again for the whole running
process...
*BEWARE: trying this method might lead to
stopping of height growth which happens to my friend... 
