Sportswear giant Nike is giving US TV viewers the chance to design their own commercials with the launch of its latest advertising campaign.

The fresh set of ads from the company invite viewers to make their own choice of how they want the action to end.

The new ads have been designed to promote Nike's Air Cross Trainer II shoe. The company is hoping people will be hooked by the short cliffhanger films that challenge viewers to race and chase top US athletes.

Sprinter Marion Jones, baseball ace Mark McGwire or snowboarding champion Rob Kingwill lead viewers through scenarios which fade to black just as they reach a nail-biting climax.

The idea is that people will be so eager to find out what happens that they will follow the onscreen message directing them to the Nike website. If they do, they will find as many as seven different endings to choose from.

Debut dash

The first spot makes its debut during the National Football League playoffs on 15 January. Sprinter Jones will challenge the viewer to a race through the streets and alleys of Santa Monica in California.

As she dashes down the beach promenade, dodging pavement perfomers and tourists, the viewer slams into a man juggling chainsaws. When the roaring saws fall back to earth, the screen goes dark.

Ideally, with all the ads, the onscreen message at the end should read 'Continue at whatever.nike.com'.

However, only the ABC network has agreed to use the word 'continue' as other networks are concerned about losing too many of their viewers to the internet. Most of the ads therefore will simply carry the website address.

Nike, and the ad agency that created the films, say they have tried to give viewers a feeling of actually being in the ad.

But at least one advertising expert says he is not that impressed.

"It sure sounds interesting but it's not that much different than what Victoria's Secret did last year with their online fashion show," said Charles Frazer, an advertising professor at the University of Oregon.

He added that the Nike campaign may push the convergence of TV and the web ahead a little faster. But he also noted that the lingerie company ran into problems when access to its internet site was temporarily blocked due to heavy demand.

The Nike ads are most likely to appeal to the young, who will be the most ready to follow the action on to the web. Visitors to the website who have not seen the ad on TV first will be able to view a digitised version.