Maximum power at height

[FearlessFreep]

I was working on my stading bag this morning and I realized I was getting a lot more power out of my spinning side kick then I had thought (judging by how far the bag displaces in regards to other strikes). One thing I noticed is that I seem to get more power in a stright shot to the mid section then in a higher kick.

This had me wondering the reason. The way I see it, there could be a few reasons

1) I'm not flexible enough to get a high sidekick and still drive with power. Also possibly balance in that with a lower kick I have more balance so it's easier to drive more power into the target (in other words, my lack of experience makes the lower kick more powerful than a higher kick)

2) I'm driving upward into a vertical surface so the energy from the strike is a bit wasted on this kind of target and would be different against a live target

3) Bio-mechanics. The structure of the hips, legs,etc...simply makes the the alignment of everything work more powerfully when going straight out from the body then up.

If it's the first then I just need to practice more. If the second then I just need to set my expectations for knowing what the reaction of the bag means in terms of what I did. If it's the third than I just need to keep that in mind when choosing kicks versus targets versus desired results.

If it's something else or some combination or...

...anyone have thoughts?

Is this true with other kicks? Are there biomechnical realities that impinge themself upon the power of certain kicks at certain heights or...

[FearlessFreep]

Oopps...meant to put that in the TKD forum....

[MJS]

MOD Note

Thread moved to TKD per request in post #2

MJS

MT Mod

[barriecusvein]

As you are kicking a vertical surface, the force put 'into' the bag falls off as the product of the force of your kick and the sin of the angle between the bag and your leg, so F(bag) = F(kick)sinφ (sorry for the maths mumbo jumbo, i'm a physicist, spoiling things by using maths is what i do!).

In reality, this means the maximum power from your kick will be transmitted into the bag when you strike it with a completely horizontal kick. So pretty much your second point. Theres not much you can do to avoid this loss of power, short of growing an extra 4 feet so your new horizontal kick is where the old high one was.

As you say though, against a live target you will probably be aiming to drive the kick into the throat or neck, where the surface you are hitting is not vertical, so much more power can be transmitted.

Also, i would imagine there will be biomechanical reasons for less power because the muscles have to lengthen to allow your leg to get higher. This means they can contract less when you throw the kick so they generate less power.

[TigerWoman]

In WTF TKD, the power comes from the snap. Also as you get more conditioned and your core, balance, flexibility and strength in your legs get stronger, your high kick gets stronger too. I wouldn't do a spin heel (hook) to a bag though as you will hyperextend your knee. Better to do that on a paddle or a target that gives. TW

[FearlessFreep]

A little bit of the first one and a little bit of the second.

Well, I can work on that :)

Thanks

[Martial Tucker]

FearlessFreep,

First of all, I love your name. It makes me laugh and think of Yosemite Sam every time I see it.

As for your question, if I understand it correctly, I have a couple of "checks" for you. Both involve your "support leg" that you stand on as the other leg is
extending.

1. Make sure the knee of your support leg is not locked, or even totally straight when you fire the kick. If it is too straight, or locked, it will affect your balance and ability to kick higher with power. Your support knee should have a slight bend to it. Think of the support leg as more of a shock absorber than a support.

2. The heel of your support foot should be pointing right at your target.


These are fairly basic things, and I'm guessing you've got them under control, but whenever I hear the question you asked, these are the first things I always check.

[FearlessFreep]

Good calll on the Yosemite Sam reference. I did some stupid stunts as a kid so my dad started calling me that and it makes a good 'net nickname

#2 I have down. In fact I was spening some time in the restroom at work today trying some straight sidekicks and checking how my foot angle compared to the height I could get well (seem to affect hip angle which seemed to affect how much I could open up and therefor how high I could get....maybe I'm crazy but I definitely know that one!)

#1 I admit I really don't know, I'll have to check. I had not thought about that so I'll have to see what I'm doing

Thanks!

[Marginal]

Any kick is always going to be more powerful when it's level with the hips. You always sacrifice power and range the higher you go with a standing kick. No amount of training's going to overcome biomechanics. (Reed Richards might pull it off.) If you want to deliver full power to a higher point, that's what jump kicks are for.

[FearlessFreep]

Thanks, Marginal, I'll keep that in mind. Like I said, "desired outcome vs target vs kick"

[jdinca]

Marginal beat me to it. The same goes for arm strikes straight off the shoulder.

[TigerWoman]

I wouldn't say no amount of training will provide power as a spin heel is pretty elemental in WTF TKD. That's defeatist. The snap does provide the power. We go from a one hand hold, to two finger hold, to a dropped board, to 360 blind folded --all spin heels. We add on the jump, yes to increase power so that the two finger hold is possible for a black belt candidate. I had to do the dropped board for 2nd dan with no jump so as your power increases the possibilities increase. My instructor's legs are actually shorter than mine, he has less flexibility too but his core and leg power is stronger. Keep practicing. TW

[Marginal]

I wouldn't say no amount of training will provide power as a spin heel is pretty elemental in WTF TKD.

With all due respect, that's not what I said. I said power is sacrificed (as is range) as the kick's raised. That means a kick at hip level's at optimum power. A head kick will be less powerful, but that does not mean the kick will be powerless. You can train to deliver a powerful head kick, but you will still be physcially capable of delivering a stronger kick at hip level. You're not training to offset that power loss. It's built in. You're training to increase overall power.

[FearlessFreep]

If I can guess, I think Marginal's point was not about the power of the given kick per-se but more about relative power between kicks. In that however powerful a given high-kick is, your same verion of that kick is going to be even more powerful at a medium level. I don't think he was implying that you couldn't make that high kick powerful, just that it wil never be as powerful as the same kick at hip level. The more powerful the high kick, the still more powerful the medium kick.

I don't know enough to say if that's true or not, which is why I'm asking these questions after all, just trying to clarify what I think he was trying to say

-------
...and I started that post before Marginal did his but I typed too slow : )

[Martial Tucker]

With all due respect, that's not what I said. I said power is sacrificed (as is range) as the kick's raised. That means a kick at hip level's at optimum power. A head kick will be less powerful, but that does not mean the kick will be powerless. You can train to deliver a powerful head kick, but you will still be physcially capable of delivering a stronger kick at hip level. You're not training to offset that power loss. It's built in. You're training to increase overall power.
I agree with this, but the good news is, as you kick higher and higher against an opponent's body it takes less and less power to move/unbalance them because you are moving your force higher and higher above their center of gravity. That's not to say I personally favor high kicks, because I don't. It's very rare that I would kick above waist level, but I know if I do go high for a "change-up", the natural loss of power is largely, if not completely offset by my opponent's center of gravity being much lower than where I am striking him.

[FearlessFreep]

Not to mention shock value of getting a heel in the face...

[Martial Tucker]

Not to mention shock value of getting a heel in the face...
'Tis more blessed to give, than receive........:btg:

[TX_BB]

I was working on my stading bag this morning and I realized I was getting a lot more power out of my spinning side kick then I had thought (judging by how far the bag displaces in regards to other strikes). One thing I noticed is that I seem to get more power in a stright shot to the mid section then in a higher kick.

This had me wondering the reason. The way I see it, there could be a few reasons

1) I'm not flexible enough to get a high sidekick and still drive with power. Also possibly balance in that with a lower kick I have more balance so it's easier to drive more power into the target (in other words, my lack of experience makes the lower kick more powerful than a higher kick)

2) I'm driving upward into a vertical surface so the energy from the strike is a bit wasted on this kind of target and would be different against a live target

3) Bio-mechanics. The structure of the hips, legs,etc...simply makes the the alignment of everything work more powerfully when going straight out from the body then up.

If it's the first then I just need to practice more. If the second then I just need to set my expectations for knowing what the reaction of the bag means in terms of what I did. If it's the third than I just need to keep that in mind when choosing kicks versus targets versus desired results.

If it's something else or some combination or...

...anyone have thoughts?

Is this true with other kicks? Are there biomechnical realities that impinge themself upon the power of certain kicks at certain heights or...


It’s kind of none of the above; your bag is sliding more because you’re hitting it closer to the bags center of gravity.

All kicks will have individual biomechanical optimizations here are some aproximates:

Back kick is near solar plexus high.
Roundhouse kick is around chest high.
Front kick is around goin level.

These general spots will also depend on each individuals conditioning and abilities.

[FearlessFreep]

It’s kind of none of the above; your bag is sliding more because you’re hitting it closer to the bags center of gravity.

Had not thought of that.

Back kick is near solar plexus high.
Roundhouse kick is around chest high.
Front kick is around goin level.

One thing that occurred to me in reading that list is that, while you didn't mention any high targets, you also didn't mention any low targets, either. I know there are people (and I've heard it said myself) who say not to kick above the waist, and I guess there are tactical reasons for it, but from this I also take it that for most kicks you're going to get your maximum powerat targets that are above the waist. A roundhouse to the knee is not going to be as powerful as a roundhouse to the chest, for the same person. I mean, there could be other tactical reasons for a roundhouse to the knee, but it's interesting to think in terms of power generation about a roundhouse to the center body versus to the knee.

This all assume a relatively standing position. There seems to be an optimal body positioning in terms of hip, leg, etc...for maximum power from a biomechanical point of view. I didn't mention it earlier but I like what TigerWoman said in that, given a certain optimal 'body shape' for power in a kick at a given height, you can use jumps to change the height of your hips in throwing the kick. So you can maintain tha optimal body positioning at different targets by changing your hip height, and thus can get that maximum power to the head not by kicking up at it from standing bu kicking sideways at it straight out from the hips, from a jump

[TigerWoman]

Any kick is always going to be more powerful when it's level with the hips. You always sacrifice power and range the higher you go with a standing kick. No amount of training's going to overcome biomechanics. (Reed Richards might pull it off.) If you want to deliver full power to a higher point, that's what jump kicks are for.

I was just quoting you about the "no amount of training is going to overcome biomechanics". You could say a direct shot into the solar plexus could be stronger-3 boards worth say, I agree with that. But I have also seen 3 boards being broken with a jump spin heel to the head. Then it would be possible to break 4 boards to the chest etc. What I had issue with was the no amount of training to be able to have the same strength, biometrics do make it possible as do other factors. TW

[Marginal]

I was just quoting you about the "no amount of training is going to overcome biomechanics". You could say a direct shot into the solar plexus could be stronger-3 boards worth say, I agree with that. But I have also seen 3 boards being broken with a jump spin heel to the head. Then it would be possible to break 4 boards to the chest etc. What I had issue with was the no amount of training to be able to have the same strength, biometrics do make it possible as do other factors. TW

But they don't. The head can't take the same level of force as the core so it doesn't matter as much if the power's reduced. Training can't overcome the decrease in range anymore than it can the loss of strength. It's still there.

[Last Fearner]

Hi everyone!

This is only my second post here at MT, and my first one on the Taekwondo forum. I am new to this group, and I'm so happy to see that everyone shows each other the respect by disagreeing without insults or name calling. I find this very refreshing compared to other internet groups.

Anyhow, I'd like to share my thoughts on the original question posted here.

Originally Posted by FearlessFreep
"I was working on my standing bag this morning and I realized I was getting a lot more power out of my spinning side kick then I had thought ...One thing I noticed is that I seem to get more power in a straight shot to the mid section then in a higher kick....
...anyone have thoughts?

Is this true with other kicks? Are there biomechanical realities that impinge themself upon the power of certain kicks at certain heights or..."

:asian: I agree with much of what has been contributed already. The angle of impact on the target has an effect, just as if a board was turned at an angle to your kick when breaking might cause the kick to deflect its power. A vertical bag is going to display the physical reaction to a kick differently if the linear strike is not exactly perpendicular to the surface. The other factor brought up is true that the center mass of the bag will cause a more abrupt displacement of the bag.

Aside from the issues mentioned about how a human body (head or torso) reacts to impact (all very good valid points, by the way), I am going to stick with the question of maximum power and biomechanics at each target level. Considering the angle of impact, imagine if you could turn the striking surface to be perpendicular to the line of your kick and measure the impact (like stomping on a bathroom scale). Would you have less power at higher kicks. My thoughts are yes. Can you increase that power? Yes, but as it has been said here, increasing your ability to strike with more force in higher kicks tends to proportionately increase the power of a mid level kick, and a low level kick.

My experience with this exercise is demonstrated by the following. When I practice breaking boards, I will place one board between cement blocks on the ground (I usually use re-breakable boards in practice to save money). I stomp through the board. Then I place the board in my board holder (a wooden framework I built to hold mulitple boards at each level). I find that beginner students who stomp through two or three boards on the ground on their first attempt often have trouble breaking one board at mid level.

Once they increase their flexibility, strengthen their muscles, and learn the balance and biomechanics of the kick, they can break one or two boards at mid level, three boards at knee level, and four boards stomping. However, they will be lucky if they can break one board at face level. In time, two or three boards at face level is not so much a challenge, but proportionately they can then break four at mid level, five at knee level, and six by stomping on the ground (wooden pine in this case). I find it almost as easy now to break six at mid level as I do stomping - but that's just me - lol)

The effect of fighting against gravity, the restrictions on the muscles, and alignment of the hips are all part of the reason, as others here have suggested. Another reason is that the "Applied Force" at impact, or "snap" of a kick is only part of the total destructive force. The object struck automatically returns a "Reaction Force" which fights against the impact of the Applied Force (Sir Isaac Newton's law of Reaction). The board breaking skills called "Speed breaks" can only overcome some of this loss of power at impact.

If that Reaction force is allowed to dissapate, then the maximum Striking Force is reduced. However, if the alignment of the hips, and the support of the rear leg are optimal (which I keep bent in all kicks except the side kick where the locking of the knee reinforces the return of the Reaction Force from the floor), then the maximum Striking Force will be achieved. I have found this to be easier to do at a level closer to the heighth of the solar plexus because of the straight line that can be achieved from the supporting foot's heel, through both legs to the striking heel at the target - basically doing the splits from the ground to the target as you break through the boards.

I'm sure most of you were aware of all this, so I am just sharing my thoughts and attempting to connect here on what we already know. However, if anyone disagrees, then I respect that as well (I'll just scratch you off my Christmas card list) :uhyeah: - just kidding - lol

Respectfully,
Sr. Master Eisenhart

[FearlessFreep]

Thanks for that reply. (and someone needs to edit your post to close of an italic tag : )

The other factor brought up is true that the center mass of the bag will cause a more abrupt displacement of the bag.

THis just brought something to mind. The CG of a standing heavy bag is *very* low, being that it is a padded target anchored at the ground with a big sand or water filled base. What that means is that if I strike low it tends to 'scoot' across the floor, but if I strike high it tends to vibrate back and forth more, without actually moving from it's position. The human body CG is in the hips/core. Don't know how that matters from a practical standpoint, but it did occur to me so I thought I'd throw that out there and ss if it means anything in terms of training or execution.

[FearlessFreep]

One non-connected point I'll throw out there is that flexibility plays a big role in power/speed at height. The more flexible you are, the easier you stretch out, the less your muscles have to fight each other. For example, on a snap kick. Your quads are pulling up on your leg, your hamstrings are resisting in the back. The better your hamstrings can sretch before they resist, the higher you can kick before your quads are pulling against the resistance of your hamstrings, therefore the faster you can kick high, and as a result, the more power you can get into the strike

[TigerWoman]

One non-connected point I'll throw out there is that flexibility plays a big role in power/speed at height. The more flexible you are, the easier you stretch out, the less your muscles have to fight each other. For example, on a snap kick. Your quads are pulling up on your leg, your hamstrings are resisting in the back. The better your hamstrings can sretch before they resist, the higher you can kick before your quads are pulling against the resistance of your hamstrings, therefore the faster you can kick high, and as a result, the more power you can get into the strike

I know I've read somewhere also, that the hamstrings have to worked/conditioned so that they are 85-90% of quad strength. Weak hamstrings, no pulling back power. Squats are good for this. We also do bungee cord -resistance training and that helps alot with the snap. TW

[FearlessFreep]

True that. I do jump rope and squats with a resistance tube and some other leg exercises to build strength in those muscles, but also have been working a lot on stretching so the same muscles will stretch as well