Just search “Tap Tester” in the search option on this site. Something should come up. Also, there’s no real difference between sleep deprivation and being overworked, they both cause a decrease in performance that can be fixed with rest.
Any training session can cause CNS fatigue, and one where PRs are being set is more likely to do so than one with a similar volume but done with less intensity. CNS fatigue can be built up instantly or it can be accrued over time. Your system can only recover so fast, and if you cause more fatigue than you can recover from, fatigue will be built up.
An example of each of the following would be like this:
-Instant Fatigue: A day of max speed sprints followed by maximal weight work.
-Accrued Fatigue: Doing several singles @ 90% in the weight room daily for a week.
Each will result in the same thing, but the time taken to do so will differ.
The worst thing about the CNS is how deceptive the bastard is.
I’ve done many a joint injury (knee, ankle, hip, etc.) by being fooled by post-onset delay. I’d do plyos on Wednesday, and have heavy weights days/high volume days on Thursday/Friday and feel fine…until Saturday morning when I’d get this random pain somewhere. Seemingly this pain comes from nowhere!! Didn’t feel it on the last few days, AT ALL.
So its a bit fickle like that, but I think as the years of training go on and I get wiser I learn how my body works. And to what stresses it will adapt to best/what exercises will give me the best results.