I disagree. Strongly.
First off, let me say that ARC training is an extremely useful tool... when used correctly. It's a perfect way to begin a periodized schedule. It's also a great way to cool down a few times per cycle after a workout. When doing ARC training, you can get much more out of it if you train several weak techniques during the workout. Simply put, it's the best training tool going for beginners or a climber embarking on a training plan. The problem is, I have yet to see someone who employs it to it's greatest benefit. I have however, seen several people use it as an excuse.
Now, if you aren't familiar with ARC training, I'll give a brief explanation. When you climb at a high intensity, your tiny little capillaries can't provide enough blood flow to keep muscles oxygenated and keep them from being fatigued. So basically, you need a more dense capillary network to stave off a pump. ARC training is an effective way to build that network. The aim is to climb for 30-45 minutes at no more than 30% of maximum strength. You should sustain a very mild pump throughout the workout. What this does is allow the capillaries to stay fully open while keeping a steady blood pressure on the capillary walls. Your body then adapts to this pressure by creating new capillaries. Now you're an endurance monster, right?
You've now given yourself a useful tool, and the training is really ready to begin. Here's why your ARC training just isn't enough.
It's true. All those boulderers with overdeveloped backs are right... routes WILL ruin their power. The fact is, they are opposites. With endurance climbing, you ask your muscles to use as little energy as possible, though when training power, you're asking your muscles to recruit every fiber that they can. Yes, now you can stay on the wall for 45 minutes on jugs, but why do you fall off the minute you hit 3 smaller holds in a row?
2. Climbing is NOT all Physiological.
In fact, I'd argue that it's mostly NOT physiological. 4 days ago I fell off of an 11b because I was pumped. Today I climbed up it, down it, and back up it without ever getting pumped. Did my physiological endurance improve that much in 4 days? Aww hell naw. I just relearned how to be comfortable while leading with a pump. I got relaxed. I found my rhythm. It was all in my head. What is ARC training teaching you except how it feels to climb without a pump?
3. Your Project is not an ARC workout.
I'm making a big assumption here. I'm assuming that you're training because you have a goal of climbing something hard for you. I'm also assuming that your goal project isn't only 30% of your maximum ability. If it is, you have problems that I'm not licensed to fix. I'm willing to bet that if you picked a project anywhere near your ability limits, then you're going to get pumped, you're going to freak out, and the whole crag is going to hear you screaming "TAKE!!!"the minute you get that crux 3rd bolt clipped.
4. You're Taking The Easy Way Out.
Here's the problem with your easy way out... it's doesn't lead anywhere. Ok, actually it does. It leads you directly to more difficult training, but you're making a U-Turn when the hill gets steep. ARC training is the first step, and a maintenance step after that. I hate (actually I love) to be the bearer of this bad news, but there is NO easy way to getting the most out of your body. It's going to hurt. It's going to mess with your head. And it's going to be the most fun you've ever had. Might as well start now.
Just so that I'm not accused of being completely a Negative Nancy, I'll answer your very important question.... "So where the hell do I go from here?".
Well my friends, click HERE, explore a little, and ye shall be saved.