When you're outside, the Forerunner uses GPS tracking to plot your movements, instantly calculating speed, distance, elevation and even the slopes of hills. If you have a typical jogging route, you can map it by marking each turn with a flag on the Forerunner's screen. After a while, the computer begins to calculate your average pace in minutes-per-mile, and there's even a pace alert: you can set an alarm to sound if you fall beneath a certain speed. (There's also one that will go off if you're moving too fast.)

Once you know what you're capable of, you activate the Virtual Partner. As if it were a normal race, you set distance and time, and then start running. The VP starts running when you press Start, and maintains a consistent rate. If you run faster, the screen tells you how much further or how much faster you're going. If you're slow, the screen turns black, and lets you know exactly how soundly the VP is beating you. It's a great trick, because I found myself picking up my pace, desperately trying to catch up with a nemesis that was visible only on the small wrist-bound screen.

The Forerunner has other great features; it counts calories and saves lap and pace history up to two years. Still, there are problems. The device's two AAA batteries can drain fairly quickly, although they last longer if you remember to turn off the Forerunner when you're not using it. Also, like digital watches, the buttons can mean different things in different situations, so navigation takes a little getting used to.

For city dwellers, the problem is the GPS tracker itself, which needs wide open spaces to keep in touch with satellites. Manhattan's skyscrapers seem to frustrate the Forerunner, which would suddenly say I wasn't moving at all — the VP cruising on ahead — and would require a pause at a major intersection to get back on track. Since Garmin products work fine in open spaces (including Central Park), I assume this problem is limited to anyone lost in the concrete jungle.

NOTE: For the holidays, we mentioned the Forerunner's more expensive precursor, the 201. The difference between the two is that the 201 runs on a rechargeable battery and has an interface for loading workout data onto your PC.