I'm currently a 4th year student at Tufts and I think the first two years prepares you very well for Step 1. You take the standard pre-clinical classes with Biochem, Clinical Anatomy, Physiology, etc. in the first year to get the basic sciences exposure. Overall during the first year, Tufts tries to teach you how the human body works in a healthy, normal state. The second year is a bit more interesting. You take classes like Pharmacology, Pathology, Pathophysiology, etc. and start learning about how the human body works and responds to different derangements/disease. There are no shelf exams during the pre-clinical years, only during the third year, but they do administer an exam around late winter/early spring of the 2nd year that is like a mock Step 1. This exam is just like the real thing (only shorter) and is meant to highlight your strengths and weaknesses so you can tailor your Step 1 studying. Also, second semester, second year has a much lighter class load than the previous three semesters and this is done so you have more time to study for Step 1. Towards the end of second year, there are a bunch of basic science reviews designed to refresh your memory in preparation for Step 1. Second year classes are over in mid-May and third year rotations usually don't start until after July 4th so there is plenty of time to do some hardcore studying. I was very happy with my Step 1 score and overall, I think Tufts did a great job preparing us not just for Step 1 or Step 2 but for residency and beyond.