Short high forces and muscle mass on a bone change it's density/size, long light forces change a bones position/shape.

For example, in a professional tennis player there is a big difference in thickness between the dominant and non-dominant forearm bones:

This is due to that hand being used a lot more, and the pressure leads to the bone increasing in density.

But when mewing, it's about applying soft force over a longer period of time. Another example of this besides mewing, is feet. Shoes compress our feet and over time this makes them narrower. This pressure is light, but it can drastically affect your bones over time. 

 If hard forces could change the shape and position of bone, then kick boxers would instead of having very dense and thick shins, have concave, boomerang shaped shins.

@lawnmewer

Bones can experience different types of stress, different types of stress causes it to remodel in different ways. The type of stress that the maxilla experiences that causes it to expand and grow forward can be caused by shorter high forces in my opinion, the mandible follows the maxilla through chewing and the occlusion, which is a hard force. The mandible can also get thicker and denser from chewing, this is another type of stress.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993819/

"For SME, 10 to 20 newtons of force should be applied to the maxillary region only 450 to 900 gm of force is generated, which may be insufficient to separate a progressively maturing suture.^{8,9,14,15,18,23,27} Maxillary arch-width increases ranged from 3.8 to 8.7 mm with slow expansion of as much as 1 mm per week using 900 gm of force.^15"

"The basis for the rapid expansion procedure is to produce immediate midpalatal suture separation by disruption of the sutural connective tissue (Fig. 3). The rapid palatal expander as described by Haas is a rigid appliance designed for maximum dental anchorage that uses a jackscrew to produce expansion in 10 to 14 days.¹⁴ He believed that this will maximize the orthopedic effects and forces produced by this appliance have been reported in the range of 3 to 10 pounds."

Lighter forces over longer periods of time is probably superior to remodel the maxilla, the maxilla is designed in that manner, and the mandible is designed to take high chewing forces, however, I think the maxilla can respond to shorter duration high forces. What if for example you applied 3-10 pounds of force to the maxilla for 2-3 hours, this might be uncomfortable or painful, so what about 10 minutes of 3-10 pounds of force every hour for 14-15 hours? I think it could actually work. This could be achieved maybe with thumb pulling, I thought thumb pulling was ineffective initially but now I'm not sure, any dedicated thumb pullers that can chime in? I noticed when I started hardmewing that when I bit down after a whole day of mewing that my occlusion was slightly different, did anyone experience the same thing but with thumb pulling?

@lawnmewer

”Short high forces and muscle mass on a bone change it's density/size, long light forces change a bones position/shape.”

The first is appositional bone growth, yes?  That seems well understood, and happens throughout one’s lifetime.  The tennis player is a good example ... I was thinking runner (I just started running last year).

Is there a name for the second one you are referring to?  Is it another type of bone growth, or is it also considered appositional?

@sinned

”Lighter forces over longer periods of time is probably superior to remodel the maxilla”

This is the entire premise behind Vivos’ DNA system.  Treatment times are often 1-2 years, with wearing just ~12h a day on average.  Some patients go a bit longer than 2 years.