On the road to London, there are numerous marking posts for the UK's leading athletes where their form and fitness will be judged, writes Mark Woods.

As one London hopeful, with a hint of sarcasm, remarked recently: "The Olympics are run outdoors." Yet performances at this weekend's Aviva Indoor Championships in Sheffield will be scrutinised for what might they might foretell.

Jessica Ennis is among those who will use the two-day meeting in her home town to test out her winter's work. While many of her domestic peers are cosseting themselves for the summer, the 26-year-old is intent on defending her pentathlon title at next month's world indoor championships in Istanbul.

In the event at the English Institute of Sport, which doubles as the trials, Ennis will compete in the 60 metres hurdles, high jump, long jump and shot putt. It will replicate the demands awaiting in Turkey where she will likely face Tatyana Chernova, who dethroned her as world heptathlon champion in Daegu last summer.

"It will be a good competition," said Ennis. "I'm going to be competing against her throughout the year and at the Olympics, hopefully. So it will be a great opportunity to see what shape she's in. I'm looking forward to finishing off the season with a good battle."

Expectations remain high for track and field's golden girl despite her letdown in 2011. She has been addressing her fallibilities with her coach, Toni Minichiello, in an attempt to peak for what will be her first Olympics. Having missed Beijing four years ago through injury, she is all too aware of the potential perils. "I'm envisioning my journey to be quite up and down throughout the year," she acknowledged. "It would be great if everything went perfectly but, realistically, that's not always the case, so we'll see. I'm just going to take each competition one at a time and build on things that I need to work on."

Guy Learmonth, Scotland's fast-improving 800m prospect, is another looking to rebound in 2012, as 11 months ago he was fortunate to walk away unscathed from a car crash, but the minor traumas incurred were enough to wreck his immediate hopes of progress. "The whole season I was playing catch up," he admitted. "It was so frustrating. I just had to take time out and get back to training by knocking off the hard miles and endurance stuff. My speed's always there but it's taken time to get back to where I was. Hopefully, this weekend, I can show I've progressed."

Having reeled off three consecutive wins since the turn of the year, the 19-year-old Loughborough student believes he has the capacity to earn a place in Istanbul. "My training has indicated I'm in far better form than last year," he said. "I really do believe I can hit the world indoor qualifying time. It depends how fast the race pans out this weekend."

Elsewhere, the Beijing Olympian Allan Scott will go for a second UK indoor hurdles title just three races into his comeback after two years out of the sport.