Nintendo changed the game, and is still in the lead
The Wii was risky for Nintendo. This space really hadn't been explored before and since it was the first mass market motion-based console, it *had* to appeal to the average gamer. And that meant it had to have great launch titles, which it did.
End of the Couch Potato
Then Nintendo introduced the balance board and developed this wacky segment called 'personal fitness'. Early attempts (Yourself Fitness on the original Xbox) didn't really gain traction with the average couch-gamer as the console really couldn't offer you live, dynamic feedback. Then the Wii arrived.
Likely an offshoot of the hugely successful DS Brain Age and My (French, Spanish, Weight Loss, whatever) Coach personal development games, this personal fitness segment actually made the gamer feel that they were doing something positive for themselves while playing a video game with live, real-time feedback. Uber cool!
Enter the Dragon
This game genre really gained mainstream acceptance when it was recognized by insurance companies providing employee benefits...yes, the purchase of a Nintendo Wii Fit balance board is covered by many benefit packages.
Then 2nd generation fitness games supplanted Wii Sports with real fitness training on a disc. EA Active is the latest entry in this field, but Wii Fit Plus is also in the development pipeline for a Christmas release.
On the horizion
So, Nintendo broke the ground and reaped the first-to-market advantage. The Wii platform has a number of fitness based titles out and more planned for this holiday season, but the competition is closing quickly. Microsoft is slated to have amazing Project Natal motion-based interactive technology available in late 2010. And Sony's set to launch their motion-based interface tech much earlier; in spring 2010. Fitness for everyone!
Better. Stronger. Faster.
Well, the technology is there now, or will be on your brand of console shortly. Will this lead to the demise of the couch-potato gamer or will it lead to more immersive video game experiences? Perhaps both. I know that I enjoy many of the fitness challenges in Wii Sports Resort andEA Sport Active. Is this making me a more 'fit' gamer? I think so, as when I'm doing sit-ups or balance board activities, or resistance band training I know that I'm getting more of a workout than I would just zapping zombies 
Or am I just wishful thinking? The software lets me track my progress, but is it enough? For me, yes, but what about You? Do you forsee self-improvement software in your near-term future? If so, what are you looking forward to? What have you tried and has worked...or hasn't? I've shared, now it's your turn 
