Wow lots of misinformation here. Let's break it down a little.
First of all, the OP asked how to get more power. He did *not* ask the merits of hitting the break hard. Conditions are going to vary. Games vary. Rules vary. Limitations of cue ball positioning on the break vary. (break from the box, or not). For 9 ball, you rarely need a huge break. Almost every scenario can be deal with at under 20mph. In 8 ball, especially big table 8 ball, it sure is nice to be able to crush the rack.
I used to top out around 28, now it takes some practice to get over 25. However, I can hit the front ball good and square at that speed. For 9 ball, I typically break around 18 or so.
Here is an example of my controlled 9 ball break. It is mostly all arm. I lift up a tiny bit, but that really adds nothing. Check it out: https://youtu.be/YONMFmjVXFc?t=8m
A good tip for generating power without much cos in accuracy: learn how to use your stroking hand. Try this. Put your hand in a sink full of water. Make sort of a fist...that shape your hand would be in when holding the cue. Now only half submerge your hand, so the thumb side of your fist is pointing at the ceiling, and the opposite side of your fist is pointing toward the bottom of the sink. Now snap your hand closed so that you squirt water strait up in the air out of your hand. This exact motion is HUGE. When breaking, let the cue rest on your fingers. Try to learn to be aware of the moment of contact. Try to snap the cue *up* against the palm of your hand right as you are making contact. This little action can give you a LOT more power. Play around with it.
I find that my hardest breaks happen when I 1) keep my head down and *rotate* my body around a fixed axis. My back leg kicks back, which acts as a counterbalance to the motion of my arm swinging, and allows my core to more or less stay on the line of the shot. 2) Follow through to a specific point well beyond the cue ball. For me, I pick a spot about 12 inches past the cueball and try to get my tip right out to that spot. The follow through itself doesn't do anything, but it is a symptom of a good stroke. I pick a spot on the cloth to aim my tip at. I find doing this increases both my power and accuracy.
People saying its not how hard, it is speed, timing, etc....there is one and only one factor that determines the speed of your break. That is the speed of the cue tip at contact with the cue ball. Timing is only the ability to generate your peak speed at this moment. The better you can tune in to the moment of contact, the easier it will be to generate cue ball speed.
One other thing...if you look at anyone that breaks hard, the last thing you want to do is put your weight on your back foot. "Lunging off the back foot" is a recipe for low power and even worse accuracy. You want your weight on your front foot. It will stay there. You will rotate your body around this weight. Trying to "move your body" , you will never be fast enough to connect right with the cueball.
Have a look at this video. Charlie Bryant has a longer pay per view video in which he breaks down every tiny movement of the break in great detail. But this is a pretty good overview here: https://www.youtube.com/watch?v=p3U-qUPU134
Finally, but the Break Rak. No other device has helped me more with my break. It is a fantastic training aid. You will learn to control your cueball, and also to deliver the cue ball into the rack with a great pop that really gets action out of the rack. Can't recommend this thing enough!
Hope this all helps,
KMRUNOUT
First of all, the OP asked how to get more power. He did *not* ask the merits of hitting the break hard. Conditions are going to vary. Games vary. Rules vary. Limitations of cue ball positioning on the break vary. (break from the box, or not). For 9 ball, you rarely need a huge break. Almost every scenario can be deal with at under 20mph. In 8 ball, especially big table 8 ball, it sure is nice to be able to crush the rack.
I used to top out around 28, now it takes some practice to get over 25. However, I can hit the front ball good and square at that speed. For 9 ball, I typically break around 18 or so.
Here is an example of my controlled 9 ball break. It is mostly all arm. I lift up a tiny bit, but that really adds nothing. Check it out: https://youtu.be/YONMFmjVXFc?t=8m
A good tip for generating power without much cos in accuracy: learn how to use your stroking hand. Try this. Put your hand in a sink full of water. Make sort of a fist...that shape your hand would be in when holding the cue. Now only half submerge your hand, so the thumb side of your fist is pointing at the ceiling, and the opposite side of your fist is pointing toward the bottom of the sink. Now snap your hand closed so that you squirt water strait up in the air out of your hand. This exact motion is HUGE. When breaking, let the cue rest on your fingers. Try to learn to be aware of the moment of contact. Try to snap the cue *up* against the palm of your hand right as you are making contact. This little action can give you a LOT more power. Play around with it.
I find that my hardest breaks happen when I 1) keep my head down and *rotate* my body around a fixed axis. My back leg kicks back, which acts as a counterbalance to the motion of my arm swinging, and allows my core to more or less stay on the line of the shot. 2) Follow through to a specific point well beyond the cue ball. For me, I pick a spot about 12 inches past the cueball and try to get my tip right out to that spot. The follow through itself doesn't do anything, but it is a symptom of a good stroke. I pick a spot on the cloth to aim my tip at. I find doing this increases both my power and accuracy.
People saying its not how hard, it is speed, timing, etc....there is one and only one factor that determines the speed of your break. That is the speed of the cue tip at contact with the cue ball. Timing is only the ability to generate your peak speed at this moment. The better you can tune in to the moment of contact, the easier it will be to generate cue ball speed.
One other thing...if you look at anyone that breaks hard, the last thing you want to do is put your weight on your back foot. "Lunging off the back foot" is a recipe for low power and even worse accuracy. You want your weight on your front foot. It will stay there. You will rotate your body around this weight. Trying to "move your body" , you will never be fast enough to connect right with the cueball.
Have a look at this video. Charlie Bryant has a longer pay per view video in which he breaks down every tiny movement of the break in great detail. But this is a pretty good overview here: https://www.youtube.com/watch?v=p3U-qUPU134
Finally, but the Break Rak. No other device has helped me more with my break. It is a fantastic training aid. You will learn to control your cueball, and also to deliver the cue ball into the rack with a great pop that really gets action out of the rack. Can't recommend this thing enough!
Hope this all helps,
KMRUNOUT