Getting fit is becoming more fun as the first augmented reality fitness apps appear for smartphones, tablets and even PCs.
Games in which you interact with a console, such as an Xbox, without a physical controller just by moving in front of it are nothing new.
Until now, you've needed the special Kinect motion-sensing gear to detect your movement. But some new apps now use the cameras themselves to detect motion, which means that any PC, tablet or smartphone with a webcam can now start including you in alternative reality environments.
The first to take advantage of this is an app called BallStrike, which is available for Windows 8 PCs via the Windows 8 Store, and for iOS and Android devices.
In BallStrike, you have to punch and blow up a series of balls that pop up on the screen around a live image of you.
The idea is that you get fit as you play, and the app even shows how many calories you're burning.
We were sceptical at first since no one has really used web cameras as motion-sensing devices for augmented reality, but BallStrike actually works.
You stand about 1.5m from your device's web cam so that you're small enough to perfectly fit an outline of you on the screen, and then start your air boxing session. It's fun and easy at first, but you have to work much harder as you move up the levels.
Available in both a free and a paid version that unlocks more levels, BallStrike proves that augmented reality will inevitably take over in the world of personal home fitness.
We're not talking about games, but apps that are designed specifically to get you fit and and which are able to track your performance and give you reams of fitness data.
They really are virtual personal trainers, unlike those that appear on the activity screens of GPS fitness watches.
Fuego's River Adventure
Another augmented reality app that helps you get fit is Fuego's River Adventure for iPad, although this one is more of an arcade game than a specific fitness app.
After your plane crashes in the jungle, you build a raft and float down a river, trying to avoid obstacles and collecting food and gold in order to survive and get home.
In reality, you're just jumping around like crazy in front of your iPad and presumably getting fit in the process. The app is basic, but it shows the potential for these kinds of games on tablets and even smartphones.
Another take on augmented reality for fitness is provided by SpecTrek — a game that uses GPS to take you hunting for virtual ghosts outside.
Point your phone or tablet camera at your surroundings and virtual ghosts pop up that you have to catch. It's fun and clever, although it gets tiring after a while, which we suppose is the point of the app.
SpecTrek, however, points to the next wave of super-interactive alternate reality games, of which the best known is Google's Ingress.
Still in closed beta (ie. being tested), Ingress turns the world and your surroundings into a giant World of WarCraft-style game in which you move around your environment and compete with other people around you.
One of the aims of the game, according to Google, is to get people out and about and fit.
The cliché that computer games make you sedentary and unhealthy may soon give way to a new kind of reality, in which the best gamers are super-fit athletes.