The Xbox One has been home to nearly a million and a half virtual workouts since the console launched in November, thanks to the Xbox Fitness app, according to Microsoft.
"We've been pretty happy with the pick up," said Dave McCarthy, general manager for Lifestyle Entertainment at Microsoft Studios. "I'm feeling really positive."
While the success of the program continues to fuel tweaks and new content, McCarthy declined to say what it will mean for the cost of the service in the coming year.
Xbox Fitness is a monthly fitness subscription service that, at least until the end of the year, is included for free with the paid Xbox Live Gold membership on Xbox One.
The service features a slew of video workouts from popular fitness trainers and programs like Jillian Michaels, Tracy Anderson, P90X and Insanity. The app blends the fitness video with the technology of the Xbox One's Kinect camera and microphone array to not just play the video, but also keep an eye on how the person working out is doing.
The peripheral and software measures a person's pulse using micro-fluctuations in the blood coursing through their face. It also tracks the energy and tempo of a person's workout and uses muscle mapping to make sure the exercises are being performed correctly.
The idea of using the Kinect to track movement and ensure it's correct, started with the Xbox 360 and its less advanced Kinect, McCarthy said.
That earlier system used a library of 200 captured moves to track performance, he said. Xbox Fitness uses a catalog of more than 2,000 and that continues to grow.
While earlier versions of Xbox Fitness tried to include audio coaching to keep a person on task, McCarthy said they ended up cutting that because it was "stomping" over what the instructors were saying. Instead, the software shows text messages on screen if you're, for instance, not lifting your knees high enough, or performing a crunch correctly.
"We're definitely looking at phones, looking at tablets, looking at PCs and figuring out how we provide a consistent user experience across our devices."
McCarthy declined to say what the plans are for the service once the year of guaranteed free play runs out. While people using the service now can get a taste of all of the different programs on the app for free, if a person wanted to train with the entire program, like, for Jillian Michaels' entire kickboxing program, they would have to pay for it.
McCarthy said Xbox Fitness has been selling some program content as well, but declined to give specific numbers.
"The key reason for getting Fitness out day one on the Xbox One launch was really to do something different in that space," he said. "We learned a lot from our forays into this space and our competitors. Our strategy is to take entertainment you love and make it better. We thought we'd make a mark on day one, even with an early adopter audience.
"The early numbers bear that out."
According to Microsoft's numbers, the largest group of people using the app are in their early 20s to early 30s, and a "healthy" number of people are coming back to the app more than once.
Future plans for the service will likely include partnering with fitness experts to create more original videos for Xbox Fitness. Tracy Anderson already teamed up with Microsoft to create and shoot the Transform program for Fitness in Hawaii.
"The advantage isn't just that the content is exclusive to Xbox One," McCarthy said, "but we can also work with her on the types of insight the program can provide."
McCarthy and his team are also looking at ways to extend the reach of Xbox Fitness beyond the Xbox One to other devices in the "Microsoft ecosystem," he said.
"We realize people don't just do stuff inside the home," he said. "We're starting to, articulate with our teams: How do we bring that experience together across our ecosystem of devices, which I think is an interesting opportunity for us as well.
"I don't know what the specific form of it will take right now, but we're definitely looking at phones, looking at tablets, looking at PCs and figuring out how we provide a consistent user experience across our devices."
Good Game is an internationally syndicated weekly news and opinion column about the big stories of the week in the gaming industry and its bigger impact on things to come. Brian Crecente is a founding News Editor of Polygon.