The 100 metres is simple. Bang! Get to the other end as quick as you can. There are minor tactical considerations in jumps and throws – deciding which heights to attempt in the vertical jumps, for example – but it’s still basically jump as high, or far, as you can; throw as far as you can.

Not so the distance events which, by their nature, take time to unfold. Even on those rare occasions when some brave soul opts to run as fast as they can, as long as they can, there is still the question of whether he or she can go the distance.

As with the race, so with the 2011 season. Change is in the air as hitherto seemingly invincible practitioners appear suddenly vulnerable. Can they hold off those banging at the gates for one more year, or will new champions emerge. How will it all unfold.

In both Beijing 2008 and Berlin 2009, Kenenisa Bekele ruthlessly dispatched all challengers to his domination of the men’s track distances. He won the 5000/10,000 metres double on both occasions – the longer distance with relative ease, the shorter with tactically complete performances.

Tirunesh Dibaba was not as dominant on the women’s side – she did not run in Berlin at all – but has been the pre-eminent performer in women’s distance events, winning the 5/10 double at the Beijing Olympic Games and Helsinki 2005 world championships, and one gold medal at every championships (except the 2004 Olympics) since Paris 2003.

With six weeks until the world championships open (with the two 10,000s on the first two days), neither is an assured participant in Daegu, though Bekele at least has assured entry as a dual defending champion. The fortunes of Bekele and Dibaba will be another element of the unfolding drama over the next few weeks.

The apparent decline of the ruling generation goes beyond these two. Many of the strongest challengers are also likely to be absent or are in questionable form.

Meseret Defar, Dibaba’s Ethiopian arch-rival, has had a patchy time of it though she, at least, looks to be building into some form, with a sub-14:30 5000 at the Paris DL followed by a 31:05 10,000 in Sicily.

Like Dibaba, though, Defar does not look the irresistible force she has been.

Elvan Abeylegesse, the former Ethiopian now running for Turkey, is another who is sidelined. She is expecting a child. Abeylegesse’s aggression in her ultimately unsuccessful attempt to thwart Dibaba in the Olympic 10,000 produced one of the most unforgettable contests of the Beijing Olympics.

Vivian Cheruiyot (5000) and Linet Masai (10,000) are the reigning world champions and the Kenyan pair are both likely to be formidable in Daegu. Cheruiyot is saying she would like to attempt the double.

On the men’s side, Sileshi Sihine, number two to Bekele in so many races, is not at his top. Two others to have challenged Bekele – Eritrea’s Zersenay Tadese and Uganda’s Moses Kipsiro – are sidetracked. Kipsiro has suffered from malaria and typhoid, though he still plans to compete in Daegu. Tadese seems to be torn between the track and the roads. All three of these athletes have solid current track times, but don’t seem to be the forces they were.

The other intriguing possibility opened up by the current situation is that a non-African runner could step up. Mo Farah – Somali born but raised in Britain – Galen Rupp and Matt Tegenkamp are all among the possible men’s 10,000 medallists. Shalane Flanagan is a threat in the women’s 10,000.

Flanagan (Beijing 2008) and Kara Goucher (Osaka 2007) have already been bronze medallists at 10,000, but neither was a factor in deciding the race. The exciting thing about 2011 is that, for the first time since Craig Mottram in the Helsinki 2005 5000 or Paula Radcliffe in women’s 10,000 before that, we are looking at a non-African runner being right in the winning mix.

 Farah has undoubtedly stepped up a level since moving to the US to train with Rupp, and others, under Alberto Salazar. His closing speed in running the fastest 10,000 of the year (at the Pre Classic) and winning the 5000 at the Birmingham DL was most impressive.

Rupp is yet to impose himself on an international race in similar fashion but, three years younger than Farah, gives every impression that he soon will.

For a different reason – injury, in his case – Mottram may still be a year away from 2005 form, but he, too, is showing every sign of getting back into contention for Daegu and London.

Flanagan showed her class in taking a bronze medal behind Cheruiyot and Masai at the world cross-country in Punta Umbria earlier this year. She also showed her development, as the previous year she had not been able to put herself right in the race.

At the US championships, Flanagan ran from the front in finishing comfortably ahead of Goucher. It seems she is a good chance to take a medal again in Daegu.

Whatever happens, there is a lot more drama to unfold in the track distance races yet.