All in core strength
I just read the abstract of a study cited by Chris Highcock at Conditioning Research. (By the way if you are interested in either strength training or hiking, check out Chris' excellent new e-book called Hillfit.) It is one of many studies that show that muscular fatigue impairs coordination. Because coordination is essentially a mental skill, this is an interesting flip side to another study I recently blogged about which shows that working on math problems makes you physically weaker.