There were very few bad moments for Jessica Ennis at the Commonwealth Games two months ago - after all, the 20-year-old finished the heptathlon with a personal best of 6,269 points and an unexpected bronze medal to add to her spoils from the previous summer - World Student Games bronze and European Junior gold.

Ennis, however, was less than thrilled when Kelly Sotherton, Britain's leading heptathlete, revealed her affectionate nickname for the aspiring young woman from Sheffield who stands no more than 5ft 5in - "Tadpole". It is hardly a flattering nickname, but it is a suggestive one - for all tadpoles turn into frogs, and who better to perform a leapfrog?

The latest stage in Ennis's evolution takes place at Loughborough University tomorrow in a meeting that traditionally marks the start of the English summer season. Among the other young talents seeking to illuminate what promises to be a rather damp afternoon are Emily Pidgeon, the European junior 5,000 metres champion, and Harry Aikines-Aryeetey, the world youth champion at 100 and 200m who is due to meet Britain's European junior champion, Craig Pickering, over the shorter sprint.

Ennis, a psychology student at Sheffield University, is aiming to brush up her technique in two of the six standard events, the 100m hurdles and the long jump. Having reviewed her Melbourne performance with her coach, Tony Minichiello - whose wife, Nicola, a former heptathlete, was in the two-woman bobsleigh team that competed at this year's Winter Olympics - Ennis concluded that there were significant improvements to be made.

Her javelin, too, requires further attention, although the benefits of a year's specialist coaching with the former world bronze medallist Mick Hill were evident in her personal best of just over 36m in Melbourne.

It bodes well for Ennis's continuing success that she should be concentrating so dutifully on her weaker points. But her experience in Australia was, all told, little short of ecstatic.

"It was a complete shock," she said. "I thought I could improve my personal best by at least 100 points, but to add more than 300 to it and get a medal was a massive surprise."

The most surprising performance of all came in the high jump. While Sotherton, who is just over 5ft 9in, performed creditably to record 1.85m en route to her first big title, the comparatively tiny Ennis managed 1.91m, a personal best by four centimetres.

The next day Ennis sat in the stands at the Melbourne Cricket Ground and watched the main high jump event. The gold went to South Africa's Anika Smit, with 1.91m. Had Ennis competed, and reproduced her effort in the heptathlon, the title would have been hers by a countback on jumps attempted.

"People were saying to me afterwards, 'Weren't you disappointed you weren't taking part?' and I suppose there was an element of disappointment," Ennis said. "But the qualifying for the high jump had been scheduled on the first day of the heptathlon, and even though there was eventually only a straight final on the day after the heptathlon, I know I wouldn't have been able to reproduce 1.91. My legs were absolutely dead."

The Sotherton-Ennis relationship mirrors the one on the eve of the 2004 Olympics between the then defending heptathlon champion, Denise Lewis, and the up-and-coming Sotherton, who went on to eclipse her senior partner in Athens, taking the bronze medal.

Lewis, too, had a nickname for her faintly embarrassed junior partner which she shared with the press - "Princess." That was news to Ennis, who said: "I'd rather be 'Princess' than 'Tadpole'."

While Sotherton lived up to high expectations in Melbourne, she acknowledged with characteristic candour the "little English girl" snapping at her heels. "She bit me quite hard," Sotherton added. Ennis, in turn, is candid about her own ambitions, which are turning towards this summer's European Championships in Gothenburg.

"We get on very well, but we are rivals at the end of the day," she said. "Obviously I hope one day I'm going to tip the balance like she did with Denise. But we'll see how it goes." On the evidence of Melbourne, it will be worth watching.