It seems that major marathons are always won in very respectable times (i.e. no more than 3 or 4 % off the world record). In contrast, many championship track races are won in very slow times (i.e. up to 10% off the world record). Why don't we see the same 'sit-and-kick' tactics ever applied to major marathons? Are the athletes just too bored by the prospect of "jogging" a 2:20 marathon?