Mark:
Here's of one of the most powerful (and controlled) breakers in the world -- the mighty Russian, Evgeny Stalev:
http://youtube.com/watch?v=PkCG3q2PDa4#t=560
He's all of 150lbs soaking wet, yet clocks in 35+ mph breaks (he was averaging that in the U.S. Open the video above was taken from). Evgeny (pronounced "yev genny" with a hard "g" sound in the second syllable, for those Russian-pronunciation-challenged like us Americans) uses shoulder, elbow, and his pectoral (chest) muscle to achieve this power. You'll notice he doesn't use any "lunging" motion at all, but rather a very smooth "forward drift" motion in his stance. He's got a very simple "cam" action going on with his arm joints, and doesn't require any additional motion from his body. Methinks Colin's on to a key point here; there is definitely a long lever action going on here, but Evgeny's attached a "clock spring action" to this long lever by using his shoulder and pectoral muscle the way he does. And he does all this with his playing cue!
In my opinion, Evgeny's got one of the smoothest, most powerful, and, for what's going on in his arm, accurate breaks around. Ask yourself, have you ever heard that kind of sound from a break? It's one thing to hear it in this video; quite another to hear it in person (the video lacks some of the auditory fireworks that seeing/hearing this live gives).
-Sean
Sean,
Having studied the break for some time now, I've watched most of the great breakers. You might notice that Evgeny Stalev is remarkably similar to Shane Van Boening. They both have that "forward drift" thing going on. However, both also gently stand up as they *back stroke*. Another similarity is that they both keep their bridge hand pretty well anchored to the table. The result is a setup that allows for a very gentle relaxed building of power. This, I think, is the reason why they are able to consistently hit the rack so square and control the cueball.
As for the body movement, here are my thoughts: can someone hit the rack in the high 20 mph range using just the arm, without moving the body? Not too likely. However, even if they could, it would seem to have to be a very aggressive movement. It would certainly be a very *short* lever and would require explosive power and speed. Remember that this power does not occur in a vacuum-there will be an equal and opposite force acting somewhere. This will require effort to keep the shoulder and the elbow from moving, and I think this can cost accuracy. By rotating the body slightly (the hips then the shoulders, like in a golf or baseball swing), you can provide a (moving) platform from which to execute this arm swing. You will notice a lot of breakers kick their leg back. This really has little to do with generating power. It is a *counterbalance*. The leg is rotating around the body in the opposite direction as the shoulders. This makes it easier to keep the spine in the same location as the shoulders (and leg) rotate around it. This can be practiced. The trade off is that initially you will have less cue ball control on the break. Soon, though, the benefit will be that it is *easier* (requires less effort) to swing the cue fast. So if you wish to break at, say, 25 mph...you *might* be able to achieve this with an arm-only swing (highly doubtful), but I would really like to see that motion result in quality cue ball control, because I doubt I would see that. If your goal is to break at 18 mph, then sure, use only your arm and you can have great cue ball control. 18 mph, though, is not always the best speed for a given table, especially in 8-ball.
I guess in summary what I am saying is that while you may get decent cue ball control at lower speeds with an arm only motion, I believe it is easier to develop good control at higher speeds using a more effortless technique, more like Stalev and VanBoening.
One last thing...I think the person that said Stalev was breaking at 35 mph in this video might want to check those numbers. The first break in the link looks like about 27 mph, not 35. Though anything is possible I guess.
KMRUNOUT
EDIT: One other thing I think is interesting. That style of breaking (like Stalev and Van Boening-a style I try to emulate) seems to result in an excellent ability to hit the head ball square, *but* seems prone to inaccuracy from top to bottom on the cueball. I often see Shane getting some unwanted follow on the cueball, and later in that Stalev video (25:35) you see him hit the head ball almost perfectly, but with too much draw and pulls it back into the corner pocket. I experience this myself, usually hitting a little bit of unwanted follow. No point here, just an observation.
