In the report, kids who were given so-called active video games to play on a Nintendo Wii didn't end up logging any more moderate or vigorous physical activity than those given games they could play sitting on the couch.

Researchers said that it's still possible playing active Wii games instead of other video games or simply watching TV could mean youngsters burn a few extra calories.

But, "is the Wii going to really contribute to getting those sixty minutes of physical activity [a day]? I don't think it will," said Jacob Barkley, an exercise scientist from Kent State University in Ohio who didn't participate in the new research.

Some public health researchers have hoped that active video games might be an alternative to outdoor play and sports for at least some of the physical activity kids need – especially for those who live in unsafe neighbourhoods where playing outside isn't always an option.

To try to see if that's the case, researchers from Baylor College of Medicine in Houston, Texas, designed every kid's dream study: they passed out Wii consoles to 78 kids who didn't already have one, and gave half the kids their choice of active game – such as Wii Sports or Dance Dance Revolution-Hottest Party 3 – and the other half their choice of inactive game, such as Disney Sing-It Pop Hits or Super Mario Galaxy.

Halfway through the study, the kids, all nine to 12 years old and above average weight, got their choice of a second game from the same category as their first.

Tom Baranowski and his colleagues tracked the youngsters for 13 weeks, testing their physical activity levels with a motion-measuring device called an accelerometer.

Accelerometer logs showed that throughout the study period, kids with the active games didn't get any more exercise than those given inactive video games.