A stack of Olympic and possibly world records will be broken on the Tokyo track over the next two weeks — but with the incredible impact of shoe technology on performance lately, nobody quite knows what constitutes great anymore.
It used to be the case that world records on the road and track were edged down by fractions of a second, often untouched for years at a time, before the next generation shaved a couple of hundredths and were rightly feted.
However, since the arrival of thick-soled, carbon-plated road shoes and now their track spike equivalent, long-standing records set by the sport's all-time greats are being obliterated and then obliterated again, to leave historical comparisons difficult if not impossible.