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[KrP1]

which is the range of Tibia/femur ratio to maintain the proper function of the limbs? i have read that the range should be maintained between 0,8 to 1.0

[FutureLengthener]

I've seen those numbers cited too, seems about right. That's the ratio of Tibia to femur right? (.8=Tibia is 80% as long as the femur?)

[cherrymouse]

As I read I'm understanding it. A very wide range of knowledge

[apoxyomenos]

Crural index=tibia/femur=TML/FBL.

TML (Tibia Maximum Length)= distance from the superior articular surface of the lateral condyle to the tip of the medial malleolus.

FBL (Femur Bicondylar Length)= distance from the most superior part of the head to a plane drawn along the inferior surfaces of the dystale condyles.

Neanderthal Man had a crural index of about 78; Homo Ergaster had a crural index of about 88.5.

[apoxyomenos]

Today the lowest crural index is found in the Lapps and it's about 79; in recent Europeans the lowest value is about 80 (mean of 82.8 minus 2.5 of standard deviation); in west africans is at its highest level: mean of 85.8 plus 2.5 of standard deviation.

[Morissette]

Generally speaking femur is 52-56% of your totally leg length

[apoxyomenos]

Generally speaking, exactly.

Solving the 1st system where:
X+Y=1
X/Y=0,78
X=tibia
Y=femur
You have that Y=56% of X+Y.

With X/Y=0,885 you have that Y=53% of X+Y.

[Zaney]

Generally speaking, exactly.

Solving the 1st system where:
X+Y=1
X/Y=0,78
X=tibia
Y=femur
You have that Y=56% of X+Y.

With X/Y=0,885 you have that Y=53% of X+Y.

Your math is wrong...

[BiggestProblem]

What happens if you tibia become longer than your femur?

[apoxyomenos]

Zaney,
If you solve the system you obtain the values above indicated. Where is the mistake in your opinion?
Let's assume that x+y=1 meter
Solving the system, in which the crural index=0.78, you get y=femur=0,56m, that related to the total length of the legs (1m) means 56%.
Same thing if you sole the system,  by taking into consideration the crural index=88.5, you get 0.53m, that means y=femurs=53% of the total length of the legs, that is 1.

[Morissette]

What happens if you tibia become longer than your femur?

Nothing you're just out of proportion

[BiggestProblem]

Nothing you're just out of proportion

For some reason I have an idea in my head that it would ruin your walking/running etc, since your body is used to the femur being the longest bone. Something along those lines.

[Zaney]

Where is the mistake in your opinion?

Look at your formula below:

Generally speaking, exactly.

Solving the 1st system where:
X+Y=1
X/Y=0,78
X=tibia
Y=femur
You have that Y=56% of X+Y.

With X/Y=0,885 you have that Y=53% of X+Y.

Now look at your quote below:

in recent Europeans the lowest value is about 80 (mean of 82.8 minus 2.5 of standard deviation); in west africans is at its highest level: mean of 85.8 plus 2.5 of standard deviation.

See it now?

[apoxyomenos]

Dear Zaney,
Thanks a lot for your important remark, but even considering 0,80 and 0,883 as the ends, by approximating unit, you get always 56% and 53%.

[apoxyomenos]

@BiggestProblem

You can read Chapter 8 ("Bipedalism in Homo Ergaster: an experimental study on the effects of tibial proportions on locomotor biomechanics") that is in the book: "The Emergence of Modern Human Walking, Running and Resource Transport" edited by D. Jeffrey Meldrum & Charles E. Hilton.

In this chapter is stated that: "we argue that whatever the evolutionary reasons for differences in crural index, relative length of the tibia has important effects on the biomechanics of human walking".

It could be really interesting and useful to know how, the ones who lengthened their tibia (so that their crural index is outside the range), find now their walking and running. I suppose that in real life the majority of LL candidates have not met, walked or run with one of them.

If they could report their opinions/feelings/thoughts I think it would be very useful to potential LLeners.

[apoxyomenos]

It would make sense to think that, if you have a crural index of=0.80 for example, in order to maintain unvaried your original biomechanics in walking and running, for each cm added to the tibia, you need 1.25cm in your femur. Viceversa. 1/0.80=1.25.

Or at least it would make sense to think that, if only one limb length is varied, the new acquired tibia/femur ratio should be still inside the normal crural index range.

If the new ratio is outside the range, only if you do it, you'll know by yourself what it means in terms, for example, of walking and running; and you could share it, totally or partially, with the others or not share it.

But of course it's all relative, each one has his/her own subjective perception of things. And if this perception is under the shadow of a not accepted height, of course you will not consider proportions and ratios, but you will focus only on a new level of height acceptable for you. And hopefully you will be forever very happy for this achievement.

[apoxyomenos]

@ LL candidates

First of all I apologize if the following consideration has been already written in the forum, but, given my relatively new membership, it's possible that I have not read it. So once again, I apologize.
Well, this time this consideration is not about biomechanics as the previous ones, but under a MERELY AESTHETIC POINT OF VIEW/VANITY, and it's the following one.

We start with 6 DATA:
1) we assume that, as many fk times it has been stated, the so called safe limit of lengthening per limb is 5CM;
2) a potential LLener will respect this limit;
3) this LLener can do only 1 surgery and has no problem of money;
4) this LLener doesn't know his/her crural index, so that he/she has two options: A) 5CM in tibiae; B) 5CM in femurs;
5) we assume anyway that this LLener is white Caucasic with a common crural index of about 0,80;
6) this LLener usually wears 3CM normal heels shoes + 1CM of lifts + 1CM of insole; and he/she still wants to wear this combination of shoes/lifts/insole after LL.

QUESTION:
Which is the limb advisable to lengthen under a merely aesthetic point of view?
In every day life we are all always dressed + shoes, we go to work, school, pubs, clubs,...etc..., and you want more height because of comparison with the others in these social contexts. No man is an island wrote once someone. Of course if you live alone in a desert island you don't give a   about height because there's no comparison. Someone said once: personality begins where comparison ends: is it useful to have a vacation in an island?

THE 2 OPTIONS:

OPTION A: 5CM in tibiae + 5CM of (shoes/lifts/insole) generate a new tibia length, when dressed + shoes, that is 10CM more respect the original one.
10CM/0,80=12,5CM of visual lack in femurs.
So when dressed + shoes, under an aesthetic point of view this lack in femurs could be perceived.

OPTION B: 5CM in femurs + 5CM of (shoes/lifts/insole).
5CM×0,80=4CM that is the increase of tibia if you want to replicate the original crural index of 0,80.
So under a visual point of view it's like you have replicated it: 5CM femurs + 4CM tibia + consider that you're wearing 1CM of heels shoes instead of the combination.

Of course it would be safer to consider just 4CM as maximum amount per segment, but once again it's all relative: with your money/time/health you do the fk you want and you do not need to justify at all. This is just my humble opinion, always respect for the ones who decide to lengthen up to 9CM or 10CM in one segment.

WHEN nked BAREFOOT IN FRONT OF A MIRROR:
So let's consider the conservative 4CM, but to add where? In femurs or in tibiae?
In ideal world you should allocate 4CM by following the original crural index, so: if X=tibia and Y=femur; we know that X+Y=4CM  and X/Y=0,80...... X=1,78CM and Y=2,22CM.

So if you lengthen 4CM in femurs, it means your knee should be 1,78CM higher; on the other hand if you lengthen 4CM in tibiae your knee should be 2,22CM lower. That means that you'll be fine in both cases.

[LLCaptain]

@ LL candidates

First of all I apologize if the following consideration has been already written in the forum, but, given my relatively new membership, it's possible that I have not read it. So once again, I apologize.
Well, this time this consideration is not about biomechanics as the previous ones, but under a MERELY AESTHETIC POINT OF VIEW/VANITY, and it's the following one.

We start with 6 DATA:
1) we assume that, as many fk times it has been stated, the so called safe limit of lengthening per limb is 5CM;
2) a potential LLener will respect this limit;
3) this LLener can do only 1 surgery and has no problem of money;
4) this LLener doesn't know his/her crural index, so that he/she has two options: A) 5CM in tibiae; B) 5CM in femurs;
5) we assume anyway that this LLener is white Caucasic with a common crural index of about 0,80;
6) this LLener usually wears 3CM normal heels shoes + 1CM of lifts + 1CM of insole; and he/she still wants to wear this combination of shoes/lifts/insole after LL.

QUESTION:
Which is the limb advisable to lengthen under a merely aesthetic point of view?
In every day life we are all always dressed + shoes, we go to work, school, pubs, clubs,...etc..., and you want more height because of comparison with the others in these social contexts. No man is an island wrote once someone. Of course if you live alone in a desert island you don't give a crap about height because there's no comparison. Someone said once: personality begins where comparison ends: is it useful to have a vacation in an island?

THE 2 OPTIONS:

OPTION A: 5CM in tibiae + 5CM of (shoes/lifts/insole) generate a new tibia length, when dressed + shoes, that is 10CM more respect the original one.
10CM/0,80=12,5CM of visual lack in femurs.
So when dressed + shoes, under an aesthetic point of view this lack in femurs could be perceived.

OPTION B: 5CM in femurs + 5CM of (shoes/lifts/insole).
5CM×0,80=4CM that is the increase of tibia if you want to replicate the original crural index of 0,80.
So under a visual point of view it's like you have replicated it: 5CM femurs + 4CM tibia + consider that you're wearing 1CM of heels shoes instead of the combination.

Of course it would be safer to consider just 4CM as maximum amount per segment, but once again it's all relative: with your money/time/health you do the fk you want and you do not need to justify at all. This is just my humble opinion, always respect for the ones who decide to lengthen up to 9CM or 10CM in one segment.

WHEN nked BAREFOOT IN FRONT OF A MIRROR:
So let's consider the conservative 4CM, but to add where? In femurs or in tibiae?
In ideal world you should allocate 4CM by following the original crural index, so: if X=tibia and Y=femur; we know that X+Y=4CM  and X/Y=0,80...... X=1,78CM and Y=2,22CM.

So if you lengthen 4CM in femurs, it means your knee should be 1,78CM higher; on the other hand if you lengthen 4CM in tibiae your knee should be 2,22CM lower. That means that you'll be fine in both cases.

Man, you wrote a fking essay, the fk is wrong with everyone

TLDR: I'm fking short, I have fking problems, I'm making these numbers up, I'm gay.

[BiggestProblem]

For me its just fun doing the math. I could care less about rhe proportions.

[apoxyomenos]

@LLCaptain

Speak for yourself, if you like it in the a..s, don't summarize for others. Thanks.

[Ozymandias]

@ LL candidates

First of all I apologize if the following consideration has been already written in the forum, but, given my relatively new membership, it's possible that I have not read it. So once again, I apologize.
Well, this time this consideration is not about biomechanics as the previous ones, but under a MERELY AESTHETIC POINT OF VIEW/VANITY, and it's the following one.

We start with 6 DATA:
1) we assume that, as many fk times it has been stated, the so called safe limit of lengthening per limb is 5CM;
2) a potential LLener will respect this limit;
3) this LLener can do only 1 surgery and has no problem of money;
4) this LLener doesn't know his/her crural index, so that he/she has two options: A) 5CM in tibiae; B) 5CM in femurs;
5) we assume anyway that this LLener is white Caucasic with a common crural index of about 0,80;
6) this LLener usually wears 3CM normal heels shoes + 1CM of lifts + 1CM of insole; and he/she still wants to wear this combination of shoes/lifts/insole after LL.

QUESTION:
Which is the limb advisable to lengthen under a merely aesthetic point of view?
In every day life we are all always dressed + shoes, we go to work, school, pubs, clubs,...etc..., and you want more height because of comparison with the others in these social contexts. No man is an island wrote once someone. Of course if you live alone in a desert island you don't give a crap about height because there's no comparison. Someone said once: personality begins where comparison ends: is it useful to have a vacation in an island?

THE 2 OPTIONS:

OPTION A: 5CM in tibiae + 5CM of (shoes/lifts/insole) generate a new tibia length, when dressed + shoes, that is 10CM more respect the original one.
10CM/0,80=12,5CM of visual lack in femurs.
So when dressed + shoes, under an aesthetic point of view this lack in femurs could be perceived.

OPTION B: 5CM in femurs + 5CM of (shoes/lifts/insole).
5CM×0,80=4CM that is the increase of tibia if you want to replicate the original crural index of 0,80.
So under a visual point of view it's like you have replicated it: 5CM femurs + 4CM tibia + consider that you're wearing 1CM of heels shoes instead of the combination.

Of course it would be safer to consider just 4CM as maximum amount per segment, but once again it's all relative: with your money/time/health you do the fk you want and you do not need to justify at all. This is just my humble opinion, always respect for the ones who decide to lengthen up to 9CM or 10CM in one segment.

WHEN nked BAREFOOT IN FRONT OF A MIRROR:
So let's consider the conservative 4CM, but to add where? In femurs or in tibiae?
In ideal world you should allocate 4CM by following the original crural index, so: if X=tibia and Y=femur; we know that X+Y=4CM  and X/Y=0,80...... X=1,78CM and Y=2,22CM.

So if you lengthen 4CM in femurs, it means your knee should be 1,78CM higher; on the other hand if you lengthen 4CM in tibiae your knee should be 2,22CM lower. That means that you'll be fine in both cases.

Excuse-moi, but...



Now, in all seriousness, I respect what you said (from your writing you seem to be an intelligent person), but I think that all this focus on proportions is going off the rails. If you do a "safe" amount, like 4 cm, no one will give a damn about your proportions, and if you do a "extreme" amount, like 10 cm, you should be much more worried about your recovery. Don't you think so?

[apoxyomenos]

@ Ozymandias

Of course I think so, it's what I've written not in words but in numbers...

[apoxyomenos]

...and numbers are not words in the air, are numbers.
With words you can say whatever you want, but not with numbers. So, mine was the Pythagorean objective explanation. For Pythagoras numbers were the arche (= a Greek word with primary senses beginning, origin, source of action....the principle of everything). One of the 1st thing you learn at school when you're a kid is the Pythagoras theorem...

[Whimsical]

Are you a matemathician? You seem quite knowledgeable in numbers and proportions

[apoxyomenos]

No, but before altering the tibia/femur ratio for good, the Math above that I have written, could be eventually useful to someone.