Updated: Nov 19, 2018
How does sport massage actually work at a molecular level? In brief, it switches off a muscle's inflammatory response (like Ibuprofen and aspirin do) and stimulates the production of mitochondria (a cell's energy supply). The result of both of these processes is a faster healing time for tired muscles and enhanced endurance levels.
I can't imagine volunteering to have my legs cut open to prove this, but some brave souls did... Here's a link to a short article in the Wall Street Journal detailing the research: https://blogs.wsj.com/health/2012/02/01/what-massage-really-does-to-your-muscles/?fbclid=IwAR1Fmz_P1MuvrjAo232vuNEerfgw8Y3sIVWPKbUjhJtjMnE8blR3dl1vLEg