In 1920, James B. Mennell divided massage into two categories: mechanical actions and reflex actions. The former moved venous blood and lymph and stretched connective tissue, which affected tendons and scar tissue. The latter stimulated tactile skin receptors and induced soft tissue to relax or contract, depending on the stroke. His theory is based on work with wounded during the war.
(Source: Massage – Its Practice and Principles (1920) by James B. Mennell, www.chestofbooks.com)