When you work out, stress on the muscle activates chemical pathways that increase the rate of synthesis, so now the net effect is to build muscle tissue. The muscle damage ('tearing') you mention is one signal for synthesis, but there are many more (metabolic, hormonal, dietary, etc)....
Although tuition varies greatly by year and has significantly increased over the last decade, medical school averages $34,592 per year and $138,368 per degree for in-state students at public schools and upwards of $50,000 per year or well over $200,000 for private institutions as of 2017.
How much does medical school cost in the US (average): How much does medical school cost in Europe (average): So it is quite obvious that studying medicine abroad in Europe is a much more affordable option to most pre-med students.