I wonder if it's better than stopwatch double click, lol!
For the most part, now days, I use walking to judge my CNS. It's become very easy for me to tell how fatigued I am, simply by seeing my pace per effort during a slightly hard fast walk. It's pretty incredible IMHO.
At my current level, if i'm experiencing significant fatigue (physical or CNS), it's hard for me to hit low to mid 14:XX pace (which is basically 4-4.1 mph or so. When i'm feeling fresh & my best, I can easily hit 12:XX pace, which is closer to 4.6-5 mph.
For it to be accurate, I need at least 1 warmup mile, then a solid effort for the 2nd mile. So ~30 minutes to figure out how fresh I am.
I've been so fatigued (physical + CNS) that it was hard for me to get under 16:XX-17:XX min/mi etc.
If I was using this as an AREG tool, i'd do it in the morning then base my training off of it.
You going to try any of these apps?
EDIT: Also, that moment when the app tells you that you aren't ready, but you feel ready as fu*k.. has to be a weird moment. LMFAO.
pc!