To see how these products tracked athletes' movement, we covered some ground. We logged literally thousands of miles, mainly on foot. Whether those feet were in running shoes, mountaineering boots, or backcountry ski gear, our testing was real-world and comparative. We would regularly wear and compare multiple contenders on the same endeavor. However, to truly get a feel for each device we made sure to use each one exclusively for at least a week of training. Our lead test editor, during the multi-year testing period, tackled his most ambitious training regimen ever, logging an average of seventeen training hours a week, for forty weeks. He also visited three countries on two continents and travelled more new-to-him miles than in any other period of his life. Throughout these entire two years the lead tester has maintained that same 17 hours of action a week average. Virtually every one of the lead testers abundant training hours was monitored by one or more of these GPS/Training watches. After this much usage, only a few objective comparison tests were necessary. Specifically, each tested model was used to measure the distance on a known track in order to assess accuracy. Also, we made sure to run each GPS watch tested from full to zero battery in order to test and compare it to the manufacturer's claim of battery life.