I am surprise no one has referred to this article. I think it raises a lot of very interesting points to think about:

http://www.packersnews.com/story/spo...mic/740555001/

Comments from leading trainers from rugby, soccer, etc and their much longer experiences with GPS training. My takes:

- overall NFL training is too protective, creating athletes prone to injury
- emphasis on strength, not movements makes them susceptible to non contact injuries
- using GPS for training, without corresponding info from their game activity, has minimal value
- NFL needs to better train their athletes in the activities performed when playing the game

I will leave any debate to you.