I have seen both the good, bad, and the ugly when it comes to Cross Fit. I have personally concluded that the safety and effectiveness is determined by the experience and knowledge of the Cross Fit Personal Trainer and these trainers greatly vary in ability. Do you think the Cross Fit Certification is too lenient?
I have seen the good, bad and ugly on Crossfit. The problem with Crossfit is it is a high reward that comes with high risk program. The exercises can be extremely difficult for your general population people that are out of shape. I have seen one Crossfit gym out of six I personally know do a beginner class to get members ready for being part of the regular classes. These participants cannot attend the other classes until they graduate pass the beginner classes. I thought this program had the right idea and they have fewer injuries.
I have never taken the certification, so I would not know if they teach the trainers to build up a fitness base for endurance along with form for the members.
If performed wrong, these are very dangerous and high risk exercises. I actually picked up a client very recently thanks to a crossfit studio putting a 50 year old woman in a regular class and expect her to do all the same exercise as everyone else. No modifications were given either.