FWIW: I've experimented in the past with emptying BCAA capsules into my cytomax during Base training. (SST end of the spectrum, not so much LSD)

iirc it was 1.5-2.25g BCAA, with 1.5 scoops of CytoMax, in a large WB x2.

For the initial 1-2 workouts there was a strong viceral effect of leg strength, ie. "good legs" (+10-20w for same PE near threshold).
After 5-6 workouts it seemed to go the other way, ie. "heavy legs" (down 5-10w for same PE)
This was far from a clinical method, and the heavy legs may have been just from the initial heightened intensitiy catching up with me...

Interested if Bob or anyone has insight into that experience