Which brings us neatly to my second point, which was injuries/Kwh.
Most commercial gyms don't perform exercise selection; it's done by trainers who generally focus on stuff that seems difficult and exotic because that's what brings in the business. The gyms themselves select insurance-friendly machinery.
While Crossfit gets people up off their backsides to do actual work, there's a lot of flat out stupidity mixed in with the legit stuff.
High rep Oly movements? Dumb.
High rep box jumps? Dumb.
Kipping pullups? Let's not go into that here.
Mix in the fact that a bosu ball pushup, while stupid, is less likely to cause a bulged disc than say deadlifting 65% of your DL 1RM for max reps; and suddenly we again find the quality control thing swinging back into central view.
High rep oly movements = dumb? In what situation? With what intended training effect?
Rep/weight schemes, in a periodized training program for an athlete are set to achieve a specific training goals. In one phase of the program that may be power endurance, for example. In a training program for competitive rowers high rep (30+) sets of power cleans at a low weight may be used to build power endurance.
Deadlifting 65% of 1RM for max reps is another very common exercise prescription for athletes building power endurance. If the exercise is stopped when form breaks down, I see nothing wrong here. 65% is a relatively light load. If you have a decent deadlift it's only about 300 lbs or so - a good athlete will have no trouble keep form for sets of 10+. The desired training effect of a high rep 65% effort is much different than a 85-100% max strength effort, or even a 65% low rep, speed focus.
High rep box jumps, for untrained individuals = a bad idea. If you've built up to it and have no achilles issues, this is not a concern.
> High rep oly movements = dumb? In what situation?
In all situations. This is never a good idea. Ever.
> With what intended training effect?
If it's to improve technique, do more sets. If it's to improve cardiovascular conditioning, do something else.
> a periodized training program
Oh, you mean the kind of "voodoo science" that Crossfit HQ specificially eschews and that every top level Crossfit Games competitor nevertheless follows?
> If the exercise is stopped when form breaks down, I see nothing wrong here.
I'll say it again: quality control and exercise selection.
> If you've built up to it and have no achilles issues, this is not a concern.
And yet I see middle-aged housewives doing AMRAPs on box jumps.
And it's not just repetitive strain injuries. Misjudge the jump (because, I dunno, you're really tired from high rep box jumping), land on toes, fall down, snap.
A lot of Crossfit is fine. The problems still remain that quality control is explicitly non-existent and that exercise selection is hit-and-miss with a genuine fondness for stupid ideas.
Basically, no good and safe Crossfit gym has any resemblance to Crossfit HQ's vision except to pay a licensing fee to use the trademark.