Bike Interval Clock guides you through an effective form of interval training that you can accomplish on a stationary bike in 20 minutes, three times a week. You can read more about how this method works on Lifehacker: http://lifehacker.com/5989669
The app provides you with a simple 20 minute timer that counts down to zero, but also provides you with important audio-visual cues to help you know when to start and stop your intervals. Each slow-peddling interval is 12 seconds long, and every fast-peddling (sprinting) interval is 8 seconds long. The clock turns yellow when you should slow down and plays a sound in case you aren't looking at the screen. The clock turns green when you should sprint and also plays a unique indication sound so you can hear the difference between the changes. This makes it possible to watch TV, read a book, or just do something else while you're exercising other than paying constant attention to a clock and remembering when you have to switch intervals. Aside from gaining the ability to multitask while you exercise, you won't spend 20 minutes thinking about how you're exercising (which definitely makes it less fun).
Right now the app only does this one simple thing. In the future I'd like to make it do a little more, like provide custom intervals. Please feel free to contact me with any feedback (you should find my contact info on this page, or at least a link to the Lifehacker post on this app where you can find it). I haven't tested the app much so I apologize if it doesn't work for your specific Android device. It probably will function on tablets, but it might look a little weird. If you have problems let me know and I'll do my best to fix them. Thanks!
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