CNS    CNS article

Local Neural Fatigue and Recovery

Now let's talk about local neuromuscular recovery. This is referring to recovery from the fatigue induced in the neuromuscular junctions, which join the nervous system and muscular system together. You’ve probably heard the old 96-hour rule, which says a muscle should be given 4 full days rest after an intense training session because it takes that long for it to return to full strength. This is true.  If you go in the gym today and knock out 5 heavy sets of bench presses to failure**, you'd probably have to wait at least 4 days before you'd be capable of repeating and/or beating what you did in that workout.  Does that mean it really takes your muscles that long to recover?  No, in reality, your muscles would be ready to go in about 48 hours or less, depending upon how fast they could resynthesize muscle glycogen.  But it would take the neuromuscular junction that joins your muscle and your nervous system together about that long (4 days) to fully recover so that you could produce a maximal contraction.

**Stopping each set a couple of reps shy of failure allows for quicker recovery between workouts.

"Despite the lack of evidence, neural fatigue exists and is a big factor in training."
— Eric Cressey

Imagine you deadlift 500 pounds for the first time and it's a complete grinder. You call it a day and leave the gym right after the lift. The following day, you wake up and have absolutely no muscle soreness. Just for shits and giggles, you go in and decide to test your 1RM deadlift again — because we all know you could bench heavy EVERY DAY when you were a beginner, right?
During your warm-up, you take 405 for a single and it feels painfully slow. 455 is a grinder - just like 500 was the day before. There's no way that you've got 500 in you on Day 2. What gives?
There was no muscle soreness, and it's hard to believe that a single-rep would impose so much muscular damage that it would interfere with subsequent performance. It's neural fatigue, and there really isn't any way to quantify it other than by saying that there was a decrease in performance.

 

 

BCAA and Endurance Training — The Verdict

Although it remains a promising theory, based on the current research, BCAA are not an ergogenic aid for endurance exercise in terms of delaying central fatigue onset. However, there may be other potentially advantageous effects when supplementing with BCAA for endurance exercise, as seen in the study above. More research in this area may help clarify just how BCAA can impact endurance exercise.