Other than scratching my head about the Tour of Poland starting in Italy and puzzling over the complexities of its attractivity classification – answers on a postcard, please – there wasn’t a huge amount that caught my eye tactically from last week’s racing. So instead this week, before we start to focus on the Vuelta a Espana, I’m going to talk about how the year’s final grand tour correlates with the outcome of the World Championships road race. The road to the rainbow jersey may end at the finish line in Florence, but it most definitely passes through Spain en route.

Confused? Then read on.

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It’s often said about this time of year how important the Vuelta is as a proving ground for the World Championships. But is it actually true? I’ve looked back over the results of the Vuelta and the Worlds road race over the past ten years to see if there’s any correlation between the two races. The short answer is: yes, there does appear to be.

The chart below shows that the last nine road race world champions have all at least started that year’s Vuelta, with seven either finishing on the podium or winning at least one stage. (That would almost certainly have been eight out of nine had Mark Cavendish not withdrawn ill early in the 2011 edition.)

You have to go back to Igor Astarloa in 2003 – ironically, one of the two Spaniards in the list – to find the last road race world champion who did not enter the last grand tour of the year. That’s a 90% hit rate over the past decade.

One might expect to see a similarly high rate of Vuelta participation across the other Worlds medalists, but actually that’s not the case. Looking at the same ten-year period from 2003-12, only six of the runners-up and seven of the third-placed riders in the road race – that’s 13 out of 20, or 65% – also raced in the corresponding Vuelta, a significant variance.

Based on this cursory analysis it seems that it’s not necessarily vital to race at the Vuelta if you want to finish on the podium (although it helps), but if you want to climb on to the top step in Florence next month then you’d better be at least lining up on the start ramp in Vilanova de Arousa for the team time trial in 2½ weeks’ time. (That would seem to count against the prospects of Tour de France winner Chris Froome, who will be racing at the USA Pro Challenge when the Vuelta starts.)

Is this a coincidence, or is there a degree of causality at play here? More the latter. Post-Tour de France, the Vuelta is the single biggest race where a rider can build their form against such a deep, high-quality field before the Worlds. One-day events such as the Montreal and Quebec GPs are often similar in profile to the Worlds course, but the competition is not as intense and the races do not offer quite as much conditioning benefit as a longer stage race.

Stage races such as the Tour of Poland and the Eneco Tour also feature fewer top riders, with those competing generally in developing rather than top form. At the Vuelta the parcours is tougher, the pace that little bit more intense and the competition fiercer and in top shape. Management of fatigue can be an issue, but there is no substitute for top-notch racing kilometres.

What’s more important: overall position or stage wins?

If you flip my previous analysis on its head and look at Vuelta results first, you’ll discover two more important facts from the resultant data.

Firstly, a place on the Vuelta podium is not a determinant of success at the Worlds. Quite the opposite, in fact. None of the last ten Vuelta winners has gone on to win the rainbow jersey, in either the same year or any subsequent one. Indeed, of all the Vuelta podium finishers in the past decade, only one has become world champion that year (Cadel Evans in 2009) and only one other has completed the double of Vuelta/Worlds podium finishes in the same season: Alejandro Valverde, who has, remarkably, achieved the feat three times: last year (2nd in the Vuelta, 3rd at the Worlds), 2006 (2nd/3rd) and 2003 (3rd/2nd).

The second key conclusion is that World Championships medallists are far more likely to be Vuelta stage winners than podium finishers. As I’ve already pointed out, in the period 2003-12 only Cadel Evans has gone from Vuelta podium to rainbow jersey, but six riders have won individual stages and gone on to win the Worlds road race.

And where there are only four instances of Vuelta top-three finishers converting their form into a Worlds podium finish, 11 of the 30 medallists of the past decade have done so off the back of Vuelta stage wins – including reigning rainbow jersey Philippe Gilbert’s two victories in Barcelona and La Lastrilla last year.

So there is a much closer correlation between Worlds success and Vuelta stage winners than there is with podium finishers. Is this surprising? No – not least because there are more stage winners than podium finishers in any given year. But it also makes logical sense too. A high overall finish at the Vuelta demands a GC contender’s ability to thrive on lactic acid-inducing steep gradients in the high mountains, whereas stage wins are equally likely to be shared among the hard-man classics specialists and power sprinters to whom the majority of World Championship road courses are ideally suited.

Just look at the list of recent world champions. Evans is the sole GC specialist, Cavendish the sole pure sprinter. The roll of honour is dominated by riders such as Gilbert, Thor Hushovd, Alessandro Ballan, Paolo Bettini and Tom Boonen – men with the classics pedigree to be contenders on both Vuelta stages and Worlds parcours.

It also explains the success of Alejandro Valverde – arguably the most versatile pure climber/classics puncheur of his generation – in both types of race. More so than any other rider, he is as comfortable contending for victory in the high mountains as he is in a small group sprint at the end of a hilly classic. (It is a mantle for whom Valverde’s most obvious successor is Peter Sagan.)

So what about this year?

Having said all that, this year’s World Championships road race course looks trickier than in most recent years and might well tip the balance away from the classics specialists towards the pure climbers and GC all-rounders. The early climb of San Baronto (3.9km, 7.1% average, 11% maximum) may not split the field irrevocably, but the closing 16.6km loop in and out of Florence will gradually whittle down the contenders during its ten circuits. The 6.1km, 4% Fiesole climb is not that taxing in isolation, but taken ten times in quick succession at the end of a marathon 272km race – and with a mostly downhill 11km run to the finish line – it may just favour the GC men over the stage-hunters.

What price Vincenzo Nibali – a multiple grand tour winner, top climber and ace descender – bucking the historical trend and becoming the first rider ever to win the Vuelta and the World road race in the same year – and on home soil too? It’s not often the stars align to make this combination possible. This year offers the best opportunity for many years. We’ll have to wait and see what happens.

Links: Vuelta a Espana official website, 2013 Road World Championships official website