Power is defined exactly like in the wiki article, and the units are also as in the wiki article:

The dimension of power is energy divided by time.

Breathing is largely composed, as far as my understanding goes, of four parts:

  1. inhale
  2. exhale
  3. the moment between the inhale and the exhale
  4. the moment between the exhale and the inhale

So, first, at which point in this cycle can I generate the most power for a strike?

Breathing can be done, at its most basic, in two ways. There are many more ways, which is of course why I am asking this question - if there were only two, I would have already gone through all the variations and figured this out myself.

  1. belly/diaphragm breathing (which involves raising/lowering the diaphragm when you breathe in/out)
  2. chest breathing (which involves expanding the upper chest when breathing in and contracting it when you breathe out).

Other kinds of breathing involve back breathing, reverse breathing, embryonic breathing, etc. Many methods can be found quite easily by googling, if you only know the name.

I also understand that breathing, in a vacuum (no pun intended) is completely useless. It must be done within the context of the body, but if we make abstraction of the body movements, relaxation, etc, the question remains:

Which kind of breath allows one to generate the most power for striking?

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    Interesting. I don't know if this can be conclusively proven... You'd have to control all factors as constant, changing only the breathing to have a proper experiment.
    – stslavik
    Commented Apr 5, 2012 at 22:11
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    Could you define the methods of breathing that you refer to? In particular, I've seen it argued that "diaphragm breathing" is a nonsensical term, due to the fact that all breathing in the absence of outside help is caused by the diaphragm. Commented Apr 5, 2012 at 23:29
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    In that case I recommend deleting everything after "can I generate the most power?" The second question isn't really the same as the first and the terms are poorly defined. Commented Apr 6, 2012 at 4:06
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    "No, I can't define the methods of breathing that I refer to" - if the terms aren't defined, then this is not an answerable question.
    – Bob Cross
    Commented Apr 8, 2012 at 1:15
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    I think the full answer (as stated below) really is affected by the martial art you study. I provided general principles for a still pretty general question that will point you in the right direction. Commented Apr 9, 2012 at 16:20

6 Answers 6


Before discussing what type of breathing generates power, you have to discuss how the body generates power. And even more importantly, how martial artists apply the principles of power.

Martial arts is less interested in the physics definition of power--mainly because it is of little practical use. Typically, a martial artist is interested in the force transferred to a target. Crushing a coconut requires roughly 1600 psi (pounds per square inch), which is 100 psi more than it takes to crush a skull. The martial artist isn't interested in the physics that cause the kick or the punch to generate the transfer of force, although that is done with power.

In the realm of physics:

  • Power is force over time.
  • Moving a 400lb object 2 feet in 5 seconds requires less power than moving a 400lb object 5 feet in 0.5 seconds

In the realm of martial arts:

  • Power is how much force is transferred to the target
  • Knocking a 300lb man on his butt requires more power than knocking an 80lb child

How the Body Transfers Power

This is the short summary as applies to martial arts. You can have two martial artists that can move their hands and feet with the same amount of power as defined by physicists, but the impact on the target is different. There's a few reasons to explain this, but if we eliminate external factors and focus on the budoka (martial arts students) the difference is the stability of the budoka's base. The target has force, even if it is stationary. The target absorbs some of the force, but due to surface tension, and how stable that object is, some of the force is pushed back. The budoka with the most stable connection with the ground is going to be in a better position to overcome that push back.

There is a concept that power flows from the earth through you into the target. It sounds mystical, but also has application in a physical description. When a budoka is in a solid stance, any force applied to him will be transferred to the earth. The earth has a greater surface tension than any of us, so assuming the body is rigid, the earth in essence pushes back.

The same applies when transferring the physical power of a punch or kick to a target. The more rigid the rest of the body is, the less the push back from the target is going to overcome the force applied for all the same reasons that a good stance helps the budoka. If any of the muscles used in the technique are not tense, then it absorbs some of the push back and diminishes the force applied to the target.

How this Relates to Breathing

There is a reason why we are instructed to kiya when we strike. In order to form the kiya, our core needs to tighten quickly and force an exhale. When our core tightens, it is more rigid and it becomes a strong component in our stance. This applies to both receiving and delivering a punch. Even if you don't make an audible noise, tightening the core at the moment of impact provides a good balance between stability and freely getting the breath you need.

Different arts have slightly different emphasis, with different focus on breathing and how it applies in the spirit of the art. I'll only provide a couple of examples that I'm aware of, as I wouldn't know where to find out all the answers.

  • Tae kwan do, and similar arts focus on one-hit-one-kill. Even a block is a strike. To that end, the kiya happens with the strikes and the blocks.
  • Go Ju Ryu, and some similar arts focus on prolonging your energy to fight. Breathing becomes an important part of practice. It's blocks are more of a parry to deliver a counter attack. On the block, the budoka breaths in, and on the counter strike the budoka kiyas.
  • Jujitsu, and some similar arts focus more on grappling than strikes. The budoka needs to learn how to breath while they are under pressure, as well as how to apply the techniques.

Just to throw something else in the mix, several martial arts teach the student how to fall. Typically, when the student hits the ground then need to exhale. That exhale releases tension from the body and helps prevent injury. It is also a normal reaction to the impact of hitting the earth, so it is best to learn how to control it so that when the body hits it is not too relaxed.

Regarding where the breath comes from, and all the different methods you referenced, that is highly dependent on which martial art you are studying. There are different philosophies regarding combat, and how best to survive. Applying the breathing techniques from tae kwan do in go ju ryu will leave you in a disadvantage if the fight goes longer than you expect.

With that disclaimer, breathing through the chest (chest rises and falls when you breath) is the least ideal way to breath when we need to control force. The same thing applies with singing. If your breath comes from your gut (same as diaphragm but more descriptive of how the body feels when doing it) you will usually do much better.

  • Related: martialarts.stackexchange.com/questions/432/…
    – stslavik
    Commented Apr 6, 2012 at 16:05
  • I like your answer over there. It explains rather nicely what I tried to cover as background to the real answer. I have found the more you think about different aspects of technique the less likely you will be able to do them. Active thought is much slower than muscle memory. Also, the concept of "proprioception" (understanding our own body's position) helps to make a connection of the feel of your body position with the actual techniques. Making both power (speed aspect) and technique simply automatic. Commented Apr 6, 2012 at 16:52
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    This is incorrect: "Power is force over time." You're thinking of work: en.wikipedia.org/wiki/Power_(physics)#Mechanical_power The correct definition is "Power = Force times velocity = Work over time." Power is also a poor choice as a physical principle due to it's lack of conservation. Try kinetic energy instead = 1/2 * mass * velocity^2.
    – Bob Cross
    Commented Apr 10, 2012 at 12:15
  • "Power is how much force is transferred to the target": again, you're thinking of energy.
    – Bob Cross
    Commented Apr 10, 2012 at 12:17
  • @BobCross, It's clear I'm not a physics student. I have slightly better understanding than a lay person, so the terms I use may be muddled from a pure physics standpoint. But from a lay person's viewpoint of what "power" means to a martial artist, I think I captured the intent well. Commented Apr 10, 2012 at 12:30

Which kind of breath provides the most striking power?


The crucial thing for striking is coordinating a transfer of energy between the legs/hips and shoulders/arms (even when kicking, as you're trying to use the inertia/momentum of the upper body to help the hips/legs accelerate). That transfer always involves the "gut" muscles. Whether they're twisting or crunching or just adding rigidity, they must be tensed explosively to transfer maximum power... doing so will inevitably force the diaphragm up and thereby deflate the lungs - in other words, force you to exhale.

You might reasonably ask "what if you strike immediately after exhaling - you can tense the gut without the diaphragm position rising even higher - would it be as strong? Is exhaling really part of the power equation?" No it wouldn't be as strong, not so much because exhaling is itself producing power, but because relaxing muscles and letting them stretch allows a distance over which they contract - a contraction adds power most effectively if it's pulling the surrounding body parts further - there's more motion in which any slack in the system is taken up and an efficient transfer of force made, and a longer period of acceleration leading to greater eventual speed, so the contrast in body-part positions between post-inhale and tensed post-exhale is relevant.

So - to address the "which kind of breathing" part of your question... that's a bit cart-before-horse, as the important thing is the tension and power generation, and as you refine that it'll squeeze the breath out of you however it needs to, but it'll definitely involve a relaxation/tensing expanding/contracting of your core muscles around the stomach area.

Something vaguely related - I recall TKD/HP Grandmaster Sung Soo Lee, in Sydney, mentioning research that had quantified the increase in power from actually "kihapping" (yelling) at 30%. Don't take that number too literally as measuring striking power is notoriously difficult to do meaningfully, but it's presumably vaguely indicative. I personally can't explain the physiological distinctions that make yelling relevant to power... couldn't even guess where to start... but do find a yell now and then helps me move more explosively and strike harder or even tense up to withstand a strike.

Or garlic...?


Getsugatensho? But in all seriousness, a long, controlled expelling of air from the lungs is better than a sudden puff. The reason is that you need relaxed muscles that snap like a whip on impact, rather than tensed muscles, and a sound that constricts your air passage and makes the air move faster promotes that. Which is why a "Kiai" or "Hei" is better than "Ha".

Coincidentally, it's the same rule that applies to vehicles' intake and exhaust manifolds: short and fat breaths for torque(strength) and long and thin for power(torque X RPM). I don't think the science is necessarily the same, but it's always cool to learn new things.


From an exercise science standpoint, we're looking at a few factors: muscle contraction, breathing efficiency, and metabolic function.

The body works better when only contracting or only stretching, not a mix. (The name of this principle escapes me.) So, when you are striking, you are contracting muscles to provide the force of impact, so you want to make sure you are also contracting your breathing muscles at that time (diaphragm, intercostals). You could also take advantage of this by inhaling as you engage the stretch reflex for power, and exhaling on strike.

Now in terms of breathing efficiency, you can change the type of exhalation based on the level of power you want to produce. For moderated power: use more chest for less, more abdominal for more. For full power, you'll combine chest and abdominal breathing, contracting more muscles to take advantage of the body's contraction mechanics. (Hell, if you really wanted to go for broke you could even cough, getting some of your tidal volume loose. This kind of relates to 'k' sound in various kiai, such as the word "kiai" itself. [Though please don't use "kiai"...you might as well say "punch" when you punch. ;) ])

Metabolic function is tied in very closely with the lungs of course, so as we exhale, we pour out some of the carbon dioxide in our lungs also. This helps to remove lactic acid and restore energy via the Cori cycle. If you're already hitting some fatigue, larger breaths per strike can be helpful, but the larger energy expenditure for the forced breath may be counter-productive. And knowing yourself as far as light-headedness goes (oxygen:carbon dioxide ratio) will ensure you'll still be standing to attack. ;)

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    This is a good science based answer. Anecdotally, my feeling is that compressing the torso with exhalation strengthens the frame. In internal Chinese styles, this allows greater sinking of joints which is a way of directing force.
    – DukeZhou
    Commented Apr 20, 2021 at 2:23

Based on the breathing examples provided, I assume this is primarily a question about Daoist breathing and I will answer in that context.

Which kind of breath allows one to generate the most power for striking?

Most of the breathing techniques you have enumerated are stages in the Daoist progressive process of deepening, lengthening, and relaxing your breathing. Chest breathing is a description of the normal state of breathing in Western cultures today, where the desired ideal body has a taut six-pack abdomen and large chest. Belly/diaphragm breathing is contrasted with chest breathing by emphasizing the effect of the diaphragm dropping on the belly moving. You train to make this reflexive; it becomes your new normal breathing. Once this happens, you do not switch back and forth between chest and belly/diaphragm breathing, you simply breathe. Back breathing is a similar step, where deeper breathing also begins to visibly moves the lower back. Again, it is a retraining of your breathing to a new normal; you do not switch back to chest or belly breathing. If you succeed in continuing this process to embryonic breathing, you should be the one answering questions rather than asking.

Reverse breathing is complementary to this process. At whatever your current stage of progression, you reverse the normal bellows action of your torso to, for example, expand while exhaling. This creates tension in your torso in contrast to the normal relaxation, which is often useful for striking, depending on the particular strike motion.

In summary, your breathing when striking should be normal, plus often reverse breathing.

At which point in this cycle can I generate the most power for a strike?

The end of the exhalation. During exhalation your body is most relaxed which allows you to generate speed, and it is natural to add more tension as exhalation switches to inhalation.


For striking power, it is always on the exhale (option 2), and always about mid-way or more of exhale, but never at the tail end of exhale (which is option 4).

Although you didn't ask, some things should be done close to the apex of your inhale, just before exhale (meaning, combination of options 1 and 3). If you are shooting a gun or a bow, your aim is most stable at the point you are slightly more than fully naturally inhaled (but not at maximum inhale). In other words, if your natural inhale fills up 30% of your lung capacity, your best aim is when you inhale at closer to 50% of lung capacity, and your aim tends to degrade when you fill up more than that. Each person is different, and has a different sweet spot.

So since you asked about striking, my answer would be "2" - strike on the midway of full exhalation.

If your strike is at full exhale (option 4) you will be completely gassed out and will be robbed of strength and possibly aim. If you strike on inhale, your body must handle two different direction of forces, a very difficult thing to do. It is possible, and those with capabilities of reverse breathing can do this. But it isn't natural and has to be worked at, and - to me - there doesn't seem to be must justification to switch from the natural way to do this. Perhaps others with differing opinion might offer a good reason to do it this way.

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