This is a quote from Ken Sprague who owned golds gym in the 70's regarding chiros...
I can remember back in the '70s when the written portion of the chiropractic exam was taken (surreptitiously) by the future chiropractors wife---he did the practical "manipulation" portion of the exam.
Of course, there was Cleveland Chiropractic College in LA which turned out most chiropractors at that time---high school diplomas weren't required and I knew several clearly retarded bodybuilders exploited through admission. The first attempt to read the text books sent them packing.
And in the 1980s, I owned a gym that leased space to a chiro and MD for 75% of the gross---the gym drew potential customers who had nurses as trainers; insurance covered the first 16 "therapy/workouts." All in all, it was a profitable venture---the chiro billed $35K his first month and $60K his second, not bad "rental" for <1000 square feet.
I was always amazed that everyone who walked into the chiropractic area "had a rib out"--- those statistics indicate that Los Angelenos were walking wrecks, or perhaps, profit had something to do w/ diagnoses.
Personally, I'm not a believer in chiropractic.