Here is a trick that many people are confused about. After many delays I am glad to finally be able to release it, and hopefully clear up some of the confusion.
First is the issue of if you are ready to start working on this trick. Of course there a no fixed rules in such things, but I really do recommend that you are good at Hop the Fence before seriously attempting this trick. This is basically a harder variation on that trick, so having a good handle on it first will make learning Punching Bag much easier.
The recommendations for yo-yos, string, finger protection, etc. for Inside Loops and Hop the Fence all apply to Punching Bag. Check there for more information. Also, due to the amount of force involved in this trick, I recommend not using old string or a valuable yo-yo.
In the guide for Hop the Fence, I mentioned that it was like the reverse of an Inside Loop. I also said that unlike Inside Loops, Hops will tend to want to go down. In Punching Bag your aim is to purposely fight this tendancy.
So, Punching Bag is a Hop that goes outward instead of just down, making it truely a reverse loop.
One major point of confusion is how to start this trick. A lot of people try to do it by throwing a forward pass and going from that. While it is possible to do it that way, it is fairly difficult, even more so when you are trying to learn the trick. Usually what happens when you try it that way is getting one Punch and then nothing after that.
The standard way of doing this trick is to start with regular Hops and then gradually bring them up and out. This way is also acceptable in a contest, with the count starting once the Punches have risen to the correct level.
So what is the correct level? Generally the yo-yo will always be lower than your hand when fully extended during this trick. For it to officially count, the yo-yo must come off of your hand at a 45 degree angle. Meaning half-way between straight down and straight forwards. Just raising your hand up is not enough. The yo-yo must also go outward somewhat.
Some contests used to say that the yo-yo had to stay above your waist the whole time, but this can lead to trouble. Like someone with a short string could just raise their arm up and qualify. You might want to take the waist into account as one of the factors of if you're doing the trick correctly, but the 45 degree rule is what is used by most people right now.
Note: The term Punching Bag can sometimes mean more than one thing, depending on the situation. It can either be one-handed as I am describing in this guide, or it can be one of two different two-handed tricks. A combination of a Punch and Inside Loop, or double Punches. If there is a contest situation or something else, and you aren't totally sure which one is meant, then definately be sure to ask for clarification.
Just like with Hop the Fence, the yo-yo should flip over each time. As with other kinds of loops, a dual-colored yo-yo may be helpfull in the beginning.
The effect to string tension is also the same. Punches in your right hand will make the string tighter. Punches in your left hand will make the string looser. Also, due to the force involved, your yo-yo may tend to want to stall in mid-air more than with Hops, especially at first. If that happens, just make the string tighter (if it is a fixed axle) or double-loop it.
Note: As with Inside Loops and Hops, it is possible to do this trick without the sides flipping each time. Steve Brown is one of those people that does this trick that way. However, I would discourage most people learning it this way unless you have a specific reason, as it adds difficulty to an already hard trick.
The gap width of your yo-yo and its relationship to your string are much more important to Punches then they are to Hops, since there is such an emphasis on the height of the yo-yo.
A wide gap or thin string or short string will tend to make the yo-yo loop lower. If this is taken to too much of an extreme, it might be nearly impossible to get the yo-yo up to the right level.
On the opposite end, a gap too small, string too thick or long, and the yo-yo will tend to go very high off of your wrist motion, but will also be nearly impossible to control.
If you have an adjustable gap yo-yo, it may be tempting just to make the gap as small as possible to aid in the Punches going high enough. While, a little tinkering to help with learning is fine, use moderation. You don't want to have a crutch either and learn the wrong way.
I find a good way to find a middle ground is to test with some inside loops. If the loops fall so far that they start to be difficult to control, it is probably too much. Try to find a spot where both Punches and Inside Loops are possible for you.
The angles for Punches is consistant to that of Hops and Inside Loops. Generally 1 o'clock for Punches in the right hand. 11 o'clock for those in the left hand. This is with the "clock" on the wall in front of you so to speak.
However, some people prefer to do the Punches slightly tilted inward with the yo-yos going towards the center of your body (like cattle crossing but not so severe). In that case the yo-yos might be tilted at something like 2 o'clock in the right hand and 10 o'clock in the left. Remember that the angle is in comparison to the motion of the yo-yo and your wrist, and does not have to be fixed.
Lastly, keep a close eye on the angle and your technique. It is really easy to put so much concentration on getting the Punches to go out, that the yo-yo falls over and you loose control.
Now, hopefully you know what Punches are, and a bit of how they work. Here is some more practical information to get you going.
As mentioned previously, the regular method to start is with Hop the Fence, so a Throwdown. As with Hops, it is usually a good idea to throw with the angle that you'll be using.
From the Hops, you can either slowly or quickly raise into the Punches. It is partly a matter of preference. Feel free to experiment, but also try to find some consistancy.
Here's your chance to break the rule about not moving your arm at all. Something you'll soon find out is that this trick requires a certain amount of force to accomplish. So, you need to use a combination of wrist and arm movement.
The name of the trick comes origionally from that motion. It looks a bit like someone hitting a real punching bag. While you don't want an exaggerated movement, and it can be somewhat diminished after you build up strength and technique, it is still there.
One of the first temptations to doing Punching Bag is just to raise your arm up. While your hand generally will be higher than for Inside Loops or Hops (usually around eye level), that alone will not do the trick, as the yo-yo will still be going straight down.
The real trick is making the yo-yo go outward. This is accomplished by a firm motion outward. Since the yo-yo tends to fall as you throw it out, you then lower your hand to where the yo-yo returns, and then push out and up again.
Timing is something that takes some time to feel out for Punches. You need to do the motion at the right time so that you both keep the yo-yo in control, and push it out to the right spot.
One thing to keep in mind is that it is very easy to fall into the trap of just throwing your arm out as hard and as fast as you can. You want to be as controlled as possible. Try to keep a consistant rhythm and not just speed up to try to get the yo-yo to go out.
I think that covers most of the aspects of Punching Bag. Here is some miscellaneous tips and advice for when things go wrong.
As with other kinds of loops, try to see where the yo-yo is going out to and be as consistant with it as you can. However, sometimes it is hard to tell just how far your yo-yo is going out. If you are doing it correctly or not. If you or a friend has a camcorder, it could be very benificial to tape yourself and look at what you're doing.
If you don't have that option, just asking someone if it looks like it is going out at a 45 degree angle might be enough to point you in the right direction.
You may have noticed that you do better at first, and then it just stops working. The reason is most likely just that your arms are tired. The force needed to the Punches out is greater than most other looping tricks, so unless you're used to them, it can cause trouble.
So try to take breaks from them. Just rest or do some tricks that aren't as stressfull. Flailing around when you just don't have the strength isn't going to help very much, and will be more frustrating than anything. So take breaks and maybe make this one of your tricks that you do first when your arms are still fresh.
This also applies to learning the trick in general. It might take you some time to learn the trick just because you need to build up the strength in your arms. Think about when you started doing loops and it'd cramp your hands to do more than a certain amount at a time. The same thing applies here, only to a greater degree.
Here is something I found somewhat helpfull while learning. Hop the Fence can be angled to go behind you. It is used in Ride the Horse, where the Hopping yo-yo has to be behind your leg in order for it to count as the trick.
So how does that help with Punches? Well, sometimes I liked to start the yo-yo back behind my leg. Then move the yo-yo forwards to the regular Hop the Fence position. Then try to continue that forward motion into the Punches.
Just to get used to a motion that raises the yo-yo while being somewhat easier to do. Might be worth a shot if you are having a lot of trouble.
As a last note. Keep in mind that you're sort of in a constant battle with the yo-yo. Every time you do the Punch you want to lift the yo-yo up and out. Then it will fall as it goes out and comes back to you. So then you must lower your hand and get it out again.
Remember that the yo-yo tends to follow your actions. It tends to almost be like you're punching above the yo-yo, and it follows the lead.
Also, by using the right amounts of force, timing, and movement, you can in fact raise the yo-yo up to over your head, to a Vertical Punching Bag. This movement is called a Fountain, and will be covered in a future guide. I usually find it helpfull to do the first Punches with your arm lower, and then raise up more to get past the difficult 45 degress up portion (between straight forwards and straight up). It almost feels like you're getting under the Punches and pushing them up. Good luck!