Do you need to run more to improve? Many runners seem to think so, but research suggests that there may be a better way. Since high-mileage training became the norm in the 1980s, it has been accepted unquestioningly by most middle and long distance runners that increasing your mileage will improve performance.
Unfortunately, a high mileage program leads instead to many runners becoming over-trained, which leads to poor performance, injury, even illness.
Interestingly, the facts to support this mega-mileage are sketchy at best. Renowned US physiologist David Costill established that there is a straight line relationship between mileage per week and VO2 max up to about 80 km (50 miles) per week. But there has been no definitive comparison of say, 80 km per week of steady running against 50 km of intense training.
And while running gurus like Tim Noakes recommend that you always do the minimum amount of training necessary to achieve your goals, when a marathon or a 10 K is looming, most runners tend to simply pile on the miles.
However, they may want to think twice. Long term analysis of runners has shown that while mileages above around 45 miles per week make little difference to performance, as your mileage rises above this level, your chances of injury increase dramatically.