Chiropractic
Most people don't know the training chiropractors have to complete. The core courses are the same as in medical school training, with chiropractic colleges requiring more hours in some areas. Here is a comparison.
During chiropractic college, students are required to take and pass many difficult boards, in addition to completing the rigorous education requirements needed to obtain a diploma. Upon graduation, chiropractors then have to attend/pass the last board needed to actually practice. For more information, you can refer to Hands Down Better for Certification and Licensure Information.
