[b said:
Quote[/b] ]I’m sure I have read that larger increments are better for hypertrophy, but I’m not sure I understand why.
It's simply a way to effectively stay ahead of the RBE curve. (More on this later)
[b said:
Quote[/b] ] realize we could be silly and use 25 lbs. increments and start the 10’s with 75 lbs., but that clearly is too light to be of much value. I also understand that 5-10% increments are suggested, but is there really any reason why bigger increments are better? Perhaps I’m just not understanding the use of progression properly …
It's all about making workouts productive, as you also touched. If it weren't for the CT coming to party, we wouldn't need to go for progression (no RBE, hence no need to implement a way to stay ahead of it).
Is 5 pounds enough? Yes and No. For a beginner, 5 pounds is probably plenty. But as you get more seasoned and the weights go heavier and heavier, 5 pounds become paltry. All the CT buildup would probably make that additional 5 pounds useless (or more accurately far less effective). You would need an increment larger in order to stay ahead of the curve.
I'm sure you'll ask
"but isn't SD taking care of our conditioning, and will make the CT go away? In that case, an increment of 5 pounds should remain effective for years on end, as long as I SD regularly." Again, yes and no. SD does lower your conditioning. But it really doesn't remove all the CT. CT has been found to last up to several months before going away totally. If you SD that long, you'd have wasted a lot of time and probably would lose a lot of muscle too, it's just not productive. So even after a good SD (like the suggested 9-14 days), there is definitely still some of the CT that formed due to your previous cycle - and most probably also due to the cycle before that.
Where this is going to is: the longer you train (lift weights), the more CT forms (greater/faster RBE; this is of course due to adaptation, our bodies are pretty efficient at it, except that in this case we'd really rather have hypertrophy), and the harder it becomes to "damage" the muscle fibers themselves. To continue damaging them, we have to increase weight (which is no problem since we get stronger as we get bigger; here I'm talking about the initial weight at the start of the cycle and the max weight at the end), and also the increments because RBE simply comes faster now thanks to all the adaptations that have already happened (a ton of tough CT is probably in there already).
Regards, hope that helps

-JV