Indeed, it has become one of the more important selling points of the Boston Marathon, the world's oldest and the one with the weirdest course imaginable, so imagine if you could have a similar technology available right on your wrist as with Nike+ SportWatch GPS Powered by Tom-Tom.The key difference is that rather than covering 20,000 or more runners with a system that is Marathon based, it is now down to you. In Boston, when you push off, it's flat for about two miles and then you hit a sweeper right that continues subtlety down hill into Framingham and then on into Natick along the race course.There are a couple of longish runs uphill within the Marathon, one of which is a longish uphill left-hand sweeper in Natick which leads to a straightaway that goes one for several miles until you hit the famed "Heartbreak Hill" area in between Boston, Newton, Brighton that leads to a very long downhill into Boston and the end of the Marathon.The folks at Nike thought it would be great if they could include chips that would record a runners progress with not only GPS technology and display it on their web site Nikeplus. It's a great incentive and allows those who can't get to the race to follow their favorite runner or runners without leaving their office spaces.It also allows the race sponsors to keep an eye on individual runners and if the sensor system sees something isn't quite right, it can notify emergency authorities who can dispatch a team right away. Granted, this is a blanket technology for the Marathon as it has had, in the past, as many as 26,000 runners leave Hopkinton for the 26.2 miles to Boston. So, it's of necessity that this is a rather large piece of technology,On a far more personal scale, Nike and Tom-Tom have just completed their sports watch program that individualizes your performance to the point where not only does it appear on the Nikeplus website, but you can also indicate to your friends that you have your own "personal trainer" setting your goals and reminding you of those goals daily. You don't really have to tell them it's a computer system, but it will come out soon enough, especially if you run with a group or running club so that you can compare your progress with others in your club.There's really nothing new about the technology in this system. What is new is how it is put together and what it does. For example, the running shoe sensor has been around for about 15 Marathons and GPS has been around for at least 25 years, however, when you combine them into this combination, you have a new technology that can not only act as your personal coach but also can remember: The track; The time; The distance; The Pace; The heart rate with an optional sensor; The number of calories burned; The route on Nikeplus dot com.Powering this sleek, though somewhat largish recording device -- 2.3 by 1.4 by 0.6 inches which weights 2.2 ounces -- is a next generation lithium-polymer battery.This is a somewhat a dream product for the serious runner who wants to watch his progress against others and himself or herself, but also it can watch your safety and if something goes wrong, you have Tom-Tom's active updating satellite software available to let emergency services know where you are.The system powers right up as soon as you've inserted the batteries and the Tom-Tom not only talks to the GPS system, but it also talks with the Nike system to update your running stats so that you can maintain a friendly rivalry with other members of your club and groups.In all, this is a great product of Nike's extensive experience with running and Tom-Tom's GPS experience. It's a great and healthy use of technology that will easily become a piece of your standard running gear.