On Friday, September 4, 2020 at 1:12:16 AM UTC-4, Sylvia Else wrote:
How does this actually help?

The aerodynamic forces on the craft are a function of its speed and air
density. There's not much one can do about the speed, given that the
craft is accelerating.

If the craft accelerates more slowly overall, for each speed it will be
traversing less dense air than it would do otherwise. But in that case,
is there a benefit from high initial acceleration and then reducing
acceleration on the approach to max-q?

Is it really about reducing vibration loads during max-q?

The vehicle is under more structural stress when it is under high
acceleration. Throttling down reduces the rate of acceleration and reduces
the structural stress.
.. . . . .

An external opinion --

https://www.quora.com/What-would-hap...-full-throttle
C Stuart Hardwick, Award-Winning Scifi Author, Analog regular
Answered February 23, 2018

If it passed Max-Q at full throttle, it would be accelerating at full bore
right up to Max-Q. This means it would encounter Max-Q sooner, at a lower
altitude, where the total dynamic force would be greater. This would increase
the risk of some mechanical failure, or force the rocket to be made sturdier
and heavier, reducing performance.

Someone else said rockets need to slow down before Max-Q — of course that’s a
misstatement. They only slow down their rate of acceleration, in order to
delay the point of Max-Q until they reach thinner air where the peak load will
be lower.

Max-Q is the total aerodynamic load on the vehicle. It rises with speed, but
decreases with the thinning air at altitude. Throttling down right before Max-
Q is an engineering trade-off, giving up a little of the utility of the
engines in exchange for being able to make the whole ship a little lighter.