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genkaimade
genkaimade's picture
How extended is your arm when you punch?

Hi all, A technical question for you all today : when you hit things, how extended does your arm tend to be at the moment of impact ? Or in other words, how extended should your arm be when you make contact, in order to deliver the strike with optimum power? In bare-knuckle drills etc. I find that things tend to take care of themselves on this front. However, as soon as gloves are involved or I am working a heavy bag or equivalent, I find myself having to consciously question this point as it never quite feels right, so thought I would ask. Thank you! Alex

Chikara Andrew
Chikara Andrew's picture

If I understand the question correctly regarding "optimum" power, ie. the best impact I can acheive in ideal conditions, then I would say that its almost fully extended but allowing another inch or so of travel to penetrate the target, without locking out the elbow.

However, when practicing impact on pads, bags, makiwara etc I practice at different ranges and extensions, trying to get the "optimum" impact out of every strike I can make regardless of the range. This includes punches that extend only slightly beyond my own body with the elbow at 90 degrees or less. 

Marc
Marc's picture

A technical question calls for a technical answer. ;-)

Physically speaking, a "strike with optimum power" would supposedly be a half-elastic collision in which the kinetic energy from our weapon (fist, lower arm, knee) is transformed into a maximum of deformation energy in our target (chin, neck, groin).

Therefore, the optimal moment (arm extension) of impact is when our weapon applies the most mass at maximum speed. E=m*c^2

The physical efficency of our strike also depends on the angle of impact. It should be the angle at which our target is most vulnerable and we bring the most mass into the target.

And a practical answer:

Try on focus mitts or ideally a crash-test-dummy ("Bob"). You'll see which option works best. Try different weapons at different angles.

As a general rule, there's no power at the end of the movement. I guess, you'd exert most power at about 1/2 to 2/3 through the movement, but you will need the intent to follow through.

A few more thoughts:

Real fights are messy. We'd probably not be able to control the distance precisely, anyway.

It might matter much more which target we hit. Some targets don't need that much power to cause an effect.

The rule "hit a soft target with a hard weapon, and a hard target with a soft weapon" probably makes a difference in terms of the physics involved.

It also might make a difference whether our strike is supposed to destroy (break a bone), to move the target (shake the brain in the head, kick a knee to the side to break balance), or to weaken the opponent (cognitive distraction) to set up a takedown or the devastating next strike.

Just some peaceful thoughts before bedtime. Take care.

Marc  

Quick2Kick
Quick2Kick's picture

I think f=ma is closer fit for your explanation. E=mc describes the energy the matter contains while f=ma is closer to force generated on impact. Though I'm sure a physics buff could give us a better equation taking into account change in acceleration and energy loss due to deformation plus a dozen other factors. 

As far as extension length on impact I would say the strike should be fully extended at 6in of penetration. Or put another way, upon impact the arm should be bent enough to push 6 more inches. 

Iain Abernethy
Iain Abernethy's picture

genkaimade wrote:
when you hit things, how extended does your arm tend to be at the moment of impact ? Or in other words, how extended should your arm be when you make contact, in order to deliver the strike with optimum power?

There are many times where the arm does not extend at all i.e. a short close-range hook. The power of a punch comes from the transfer of bodyweight so, if the bodyweight is moving, it is possible for the arm to remain bent in order to transfer that force.

The arm’s primary job is to transfer the power the body motion has generated. Extending through the target by extending the arm obviously helps, but there are many tactical factors to consider (not just the “physics factors”) i.e. what direction are you moving, what direction is the enemy moving, what is the angle between you both, how far apart are you, what is the height difference, what target are you hitting, etc.

People move a lot in combat so it’s often just a case of throwing the strike at the target and accepting that the enemy could move backward or forward such that the strike may land before or after the amount of extension in the arm that we may deem as the ideal. The key thing is that the bodyweight is being transferred in that direction and through the target.

There are also times where the arm will bend further on impact i.e. a close range age-zuki delivered with the back of the knuckles, a forearm strike to the base of the skull, etc.

If the enemy is right on top of you (you are against a wall, you’re clinched, etc.) then you won’t have the space to extend the arm. We need to be able to deliver the optimum shot for the circumstances we find ourselves in.

I know it’s potentially unsatisfying answer, but I would suggest the only universally right answer to the question, “How extended should your arm be on impact?” would be, “The right amount for the circumstances at the time”.

genkaimade wrote:
In bare-knuckle drills etc. I find that things tend to take care of themselves on this front. However, as soon as gloves are involved or I am working a heavy bag or equivalent, I find myself having to consciously question this point as it never quite feels right

It takes a lot of practise in a lot of different circumstances in order to be able to “intuit” how to do that (or more accurately, until the principles of power generation have been internalised such they will be subconsciously adhered to). The good thing is that you know it’s not “feeling right” which means you have an internal appreciation of what right is (and that in itself is a major achievement). I would therefore advise spending lots of time on the bag, whilst allowing the bag to freely move, such that you can practise adapting to circumstance. A good pad holder will be even better as they can give you targets in all direction (advancing, retreating, shifting clockwise, etc, etc.). The great thing about impact equipment is the instant feedback. You will instantly know from the level of impact if it was right or wrong. The percentages will shift in favour of right the more you practise.

All the best,

Iain

genkaimade
genkaimade's picture

Thank you all for the fantastic comments/advice as always! A.

Iain Abernethy
Iain Abernethy's picture

genkaimade wrote:
Thank you all for the fantastic comments/advice as always!

Thank you for the great initial question that sparked a very interesting thread!

senshido
senshido's picture

My answer would be in a similar vein to Iain's, it really depends on what kind of punch you are doing, shita tsuki (inverted gut punch) or kage tsuki (hook) would have a bent arm with your body position/movement doing a lot of the work for you.

As Iain says, a good pad holder is a great help, worth their weight in gold for a serious fighter.

swdw
swdw's picture

Done correctly, you have a multi range punch with a "traditional" linear punch. Problem is, few people practice enough to do it correctly and rotate the hand too early.

For a linear punch, if you wait until the elbow clears the ribs to rotate the hand you have

1. An uppercut position for close range- palm up

2. A vertical punch for mid range

3. A 3/4 rotated punch betwwen mid range and full reach

4. A fully rotated punch at full reach

The problem is, most karateka think the hand HAS to be fully rotated on contact, no matter what the range. This leads to sloppy punches with litle power as the elbow flairs too much and you lose connection to the major muscles in the body that drive the punch.

senshido
senshido's picture

swdw wrote:

Done correctly, you have a multi range punch with a "traditional" linear punch. Problem is, few people practice enough to do it correctly and rotate the hand too early.

For a linear punch, if you wait until the elbow clears the ribs to rotate the hand you have

1. An uppercut position for close range- palm up

2. A vertical punch for mid range

3. A 3/4 rotated punch betwwen mid range and full reach

4. A fully rotated punch at full reach

The problem is, most karateka think the hand HAS to be fully rotated on contact, no matter what the range. This leads to sloppy punches with litle power as the elbow flairs too much and you lose connection to the major muscles in the body that drive the punch.

Spot on!

In Kyokushin, the first part (palm up) is shita tsuki, followed by (1/2 rotation) tate tsuki, followed by (3/4 rotation) the impact point of the full extention to the finished article, all of these positions are practised as strikes in their own right which helps the developement of the full range technique.

Marc
Marc's picture

swdw wrote:

For a linear punch, if you wait until the elbow clears the ribs to rotate the hand you have

1. An uppercut position for close range- palm up

2. A vertical punch for mid range

3. A 3/4 rotated punch betwwen mid range and full reach

4. A fully rotated punch at full reach

For all who need something visual, watch this: