I used that technique on a road bike (actually on my MTB used as a road bike), and it did work, at least at higher speed. I tried it on the trail, not so much. Again, I believe because of the lack of speed.
Agreed on single track isn't noticeable cause there's so many other factors, but in the hardest race I've done (Shanndoah 100 with 13,000ft of climbing), I would not have gotten up that 3000ft fireroad climb sitting down and spinning at mile 70.




