It's common sense that African athletes always make a clean sweep in track events: middle or long distance races. relays, hurdles, barriers, and marathon.
In a 2010 study Geoffroy Berthelot, of France's National Institute of Sport, showed that performance in 23 out of 36 track-and-field events has stagnated since 1993.
In the beginning, the Olympic Games consisted of one main event, a 600-foot-long track race, and winners were presented with olive wreaths. Over time, there were more events and fewer clothes!