Nintendo's Wii Fit video game has become the sixth-fastest-selling games debut ever in the United Kingdom. UK sales body Chart-Track reports that in just four days Wii Fit was bought by 10 percent of Wii owners. Its sales of £16.3 million make it the third largest game launch by value (because of its steep price due to included peripheral) behind Grand Theft Auto: San Andreas and Halo 3.

Shaped like a household body scale with a white top and grey bottom, the included Wii Balance Board contains pressures sensors used to control the virtual movements. Also, the sensors are used to measure the user's center of mass and body mass index.

Wii Fit includes more than 40 types of training activities which fall into four fitness categories: Aerobic Exercise: 10-minute exercises that are designed to get the heart pumping, Muscle Conditioning: Controlled motions using arms, legs and other body parts, Yoga Poses: Classic poses that focus on balance and stretching, and Balance Games: Fun activities, such as ski jumping and heading soccer balls, which challenge the player’s overall body balance.

The players will be able to compare their results and progress on the new channel on the Wii menu. Two key measures are evaluated: Body Mass Index (BMI), a weight evaluation based on a ratio of weight to height and Wii Fitness Age, which is measured by factoring the user’s BMI reading, testing the user’s center of gravity and conducting quick balance tests.