These are just my thoughts,
Training to fatigue and to failure should be viewed as two separate things IMO.
I'm just spitballing here but this is why I think there is more value in multiple short training sessions than long sessions. Two 15 min sessions might just be better than one 45 min session. When we are fatigued we start recruiting different muscles, tendons, etc. that we wouldn't normally use potentially building improper neural pathways to the brain (I'm not saying this as a fact but more of a hypothesis). As I learn more about how the brain works it makes me wonder how things like this work. Say I'm working on wide transitions (which I have been lately). At the beginning of the session I am moving my hands at x speed and it requires x force to happen. When I'm fatigued x speed now requires x+1 to happen. Then x+2, etc. Am I building neural pathways telling my brain on this transition I need x, x+1 or x+2 to make it happen? Does my brain get confused when I'm fresh on a USPSA stage and not fatigued like I was during my session.
In the context of USPSA stages are just seconds long. Yes, fatigue does set it and we need to be able to still perform while fatigued. There's probably a sweet spot and that's what I try to find in training.
Thoughts @JCN @Clusterfrack ??