It's not convincing at all to me. There are no records or substantiation of the validity of the record, just the writer's suggestion of how they might have measured the distance and accurately timed the race. Chances are that both aspects were inaccurate, however if the writer were to suggest this then it would be a crap article.
There are records, he didn't just make it up, and he addresses the issue of measuring distance and time and how other records demonstrate that these were very likely to be accurate, obviously this is a shortened version of his work for publication in a newspaper so I appreciate it is not fully referenced and appended with statistical analysis.