I have been with CrossFit RA for 6 months now and have had a great experience. I am a very experienced runner and I bike occasionally, but no experience with weight training. As a dentist, I spend a lot of time bent over patients and my posture has suffered causing back and shoulder pain.
Since starting CrossFit, I have strengthened core muscles giving me more stamina throughout the day and improving my posture which has significantly decreased my pain levels.
One last thing, my preconceived notion of CrossFit is that it is only for experienced weight lifters and that the competitive nature and heavy lifting of CrossFit culture make you very prone to injury. CrossFit RA coaches have been great at teaching and always reminding me of proper form to improve my ability to lift as well as staying healthy while lifting.