In reply to paul mitchell:
Really interesting and good video. One thing not addressed is the assumption that volume is actually better than intensity. Most advocates of high intensity work outs emphasize the importance of rest and keeping workouts short. The idea is not to overtax your recovery ability either.
I think the style of a workout would reflect what it is you're trying to train. The high volume at moderate intensity would be most suitable for skill training. Higher intensity training, less frequently, would be suitable for recruitment.
Not too sure about the stuff about soreness either. I've seen conflicting stuff on muscle soreness. Most of the time it's admitted that we don't even understand what it is. Others claim it's only in the fascia and nothing to do with the muscles. The primary cause is eccentric contractions. I think some exercises, like kettlebell swings, it's hard not to get sore when you first start. There's a heavy eccentric component to that exercise. Even just one set can get your hamstrings sore. But most soreness goes away in a week or two if you keep doing the exercise.
Applied to climbing I think climbing, for most people, is already pretty low intensity. We get stopped often because we haven't figured out the moves or we get scared and so don't push ourselves as hard as we could.
Overall though I think what he says is really good, particularly about enjoying what you do and having fun.