In fact, Abvio developed version 6.0 of its app to take advantage of Notification Center. As CEO Steve Kusmer describes it, the app's ability to graphically present GPS-based and workout data even when the iPhone's screen is turned off may not be flashy, but it will be very useful.

All of the best-selling GPS fitness apps for the iPhone already enable users to receive a variety of audio notifications. For example, even if you're already listening to music while working out, you can set up Runmeter, , , and other apps to let you know your time, distance, and pace at pre-specified intervals. For example, I usually set up my GPS app to notify me of my overall time and pace as I reach each mile of my run.

However, I'm not able to visualize the data without turning the iPhone on--and if you've worked out using a GPS app, you know that turning on the iPhone while you're working out increases the risk that you'll inadvertently touch the screen, which may pause, stop, or interfering with the data collection process in some other equally inconvenient fashion.

Also, if you're a serious athlete whose workouts frequently last several hours, being able to use the iPhone with most of its capabilities disable--except those that are most necessary--can have a significant impact on your device's battery life. The screen display, especially, can quickly deplete battery power, so Notification Center's ability to turn on the screen for just a few seconds at a time could make the difference in whether the iPhone outlasts a marathoner's wobbly legs toward the end of a long run or not.

"Runmeter 6.0 enables you, through Notification Center, to view more than 70 different types of workout statistics on your iPhone's screen without having to turn your iPhone on manually and without activating the touch screen," Kusmer says.