Mechanical stimulation simply means introducing physical forces to tissue.
During skincare application and facial massage, those forces can include several different forms.
Pressure
Pressure occurs when force is applied against the skin.
A fingertip, roller and weighted metal tool can all create pressure, but the magnitude and distribution of that pressure can differ substantially.
Compression
Compression occurs when tissue is pressed.
Massage techniques often introduce varying degrees of compression depending on the angle and force being used.
Shear
Shear occurs when forces act parallel to a surface or when tissue layers move relative to one another.
Gliding movements across the skin can create shear.
Stretch
Skin and underlying tissue can also experience tensile or stretching forces during movement.
These forces don't exist independently. A facial massage movement may create several at once.
That is one reason simply saying “facial massage” doesn't describe a standardized treatment.
Ten minutes of light rolling isn't mechanically identical to ten minutes of gua sha.
And neither is necessarily identical to the mechanical input created while using The Applicator® during skincare application.