Also, lower forces will not cause plastic deformation, but they can cause enough deformation of the fibroblasts in connective tissues for them to begin rapid collagen synthesis. At first this will be a made up of a great deal of type III collagen and fibronectin which are both more elastic than the more common type I collagen. This will eventually mostly be converted to type I collagen, however. You will have more extra cellular matrix though, so there will be a size increase not dependent on elasticity. This is why extenders work without ever pushing the penis into the “yield” range of the stress-strain curve where true plastic deformation mostly happens. This is also why maximizing time is important with lower forces.