Referees unhappy with Sir Alex Ferguson's attack on 'unfit' Alan Wiley

Referees must undergo rigorous and regular tests and Alan Wiley is believed to have an impressive fitness record.

Sir Alex Ferguson may have claimed Alan Wiley was unfit but the 49-year-old almost certainly covered as much ground as many Manchester United players on Saturday. When the distance Premier League referees ran in the course of a match was measured recently Wiley's median was recorded as 11.5km. That, coincidentally, was the average reading for elite officials with only two covering slightly greater distances and a few managing somewhat less.

Nobody involved in top level refereeing would speak on the record today as Ferguson's comments are now the subject of a Football Association inquiry which may lead to the Manchester United manager being charged with bringing the game into disrepute. With the issue in effect sub judice the refereeing fraternity had been told to keep quiet but was privately seething at what most interpreted as an ageist attack by a manager of pensionable age who has long railed at colleagues being deemed past their "sell by dates".

Wiley is 49 and refereeing at this level due to European legislation introduced in 2006 which prevents employers forcing employees to resign on grounds of age. In 2008 Peter Walton – a top level referee and due to celebrate his 50th birthday on Saturday – used this piece of European law to stop the Professional Game Match Officials Board making him step down once he passed 48.

Whatever his age Wiley would not still be one of the 18-strong select group of referees blowing his whistle at England's leading clubs were he not extremely fit, as well as able. Like the footballers they are charged with controlling, our leading referees have their performances subjected to sometimes excruciatingly detailed analysis by Prozone and Wiley's stats are said to be impressive.

These days Premier League referees are full-time professionals earning salaries of between £60,000 and £70,000 a year and follow personalised fitness programmes with the help of personal trainers. It is hard to cheat the system as once a week they must use heart monitors, which record their exercise output for the sports scientists overseeing them.

Just to be handed a supply of heart monitors requires officials to hurdle through several hoops of flame - the most nerve wracking of which is undoubtedly their annual fitness test. First the candidates must complete six 40-metre sprints in a minimum of 6.2sec per sprint with a recovery time ofno more than 90 seconds between each run. Then they have to run 150m 20 times in swift succession in a maximum time of 30 seconds on each occasion. Again a 90 second ceiling is placed on the interval recovery periods.

Should a referee be injured for four weeks or more for any reason they must repeat the test again. They also face mid-season fitness assessments. Quite apart from their running ability referees have their blood pressure and iron levels – which affect aerobic performance – monitored along with cholesterol levels and body fat ratios. Body fat content in excess of 20% is seriously frowned upon. The additional time to devote to working out as opposed to holding down a full time job enables referees to remain fitter for longer. Allied to constant assessments which can see them discreetly dropped from the elite list, most officials typically tend to retire when niggling injuries and increased recovery times begin taking their toll.

Signficantly a 2008 survey by sports scientists in Leeds which measured the performances of 22 referees aged between 31 and 48 over four seasons found that the older refs - in the 43-48 bracket - on average covered marginally shorter distances and sprinted at fractionally lower intensity than their younger counterparts. Yet in terms of being close to both the ball and fouls there was absolutely no difference between young and old. Just like ageing footballers, it seems that older referees understand the benefits of economy of effort and fully taxing their brains rather than their legs.