I just got into crossfit this June. It is definitely something different from the regular gym. The box I go to makes us lift before we do the WOD. After 2 months of crossfit I tested my max for deadlift and squat and I was able to do 315 for both of them. It is definitely not for beginners if you never done any olympic style lifting before. Also, I would never recommend trying to do Rx(prescribed) if you cant get through half the workout without dropping down the weight. Crossfit will never replace the regular gym unless you incorporate regular lifting along with the WODs. Some of those videos idk wtf they were doing. But here are 2 videos from the box I go too.