By Sarah Holt BBC Sport in Melbourne

Sotherton's javelin throwing is a major chink in her armour

Commonwealth Games heptathlon champion Kelly Sotherton says she will struggle to win more silverware unless she makes major improvements to her performance.

The 29-year-old is unhappy with her overall display in Melbourne, despite claiming her first major title.

"I won gold but I'm disappointed with my performance - it wasn't exceptional," Sotherton told BBC Sport.

"I will only have a chance of a medal at the Europeans this summer if I improve in all my events."

Sotherton finished with a total of 6398 points - 149 points below her personal best and 489 points behind Olympic and world champion Carolina Kluft's best score in 2005.

Sotherton claims heptathlon gold

The Isle of Wight athlete again struggled with the javelin, throwing just 32.04m, but is determined to conquer her Achilles heel.

"I won't win another major medal if my javelin continues to be so poor," said Sotherton.

"It is frustrating because my performances in competition don't reflect what I can do in training. At home, I've thrown five or six metres further than that in the snow.

"The problem is me and I have to find a way in the next five months to get better."

It's good to have someone snapping at my heels because it keeps me motivated Kelly Sotherton on England's bronze medallist Jessia Ennis

Nonetheless, Sotherton, who is at least looking forward to being introduced as the Commonwealth champion, says her victory in Melbourne will stand her in good stead for the Europeans.

She will face arch-rivals France's Eunice Barber and Kluft on home soil in Gothenburg.

"The win here will give me a little bit of confidence ahead of the Europeans," she said.

"It will, of course, be a totally different set of people to contend with apart from the English contingent.

"But all my focus is on the 2008 Olympics and every competition between now and then is a stepping stone along the way.

"An Olympic medal is so hard to come by. I came out of nowhere and won bronze but that is unusual."

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By the time Beijing comes around, Sotherton could have serious competition from England team-mate Jessica Ennis, who took bronze in Melbourne.

Sotherton, now a seasoned athlete despite only receiving going full-time three years ago, is delighted to see the next generation coming through.

"It's good to have someone snapping at my heels because it keeps me motivated," said Sotherton.

"Jessica is amazing but I've told her that now she will have to learn to compete under pressure as everyone knows what she can do now."