No, smaller does not = more flexible.

There are a lot of factors that determine flexibility. Probably be best to make another thread if we want to have that discussion, though XD

Wow!! How would that be? lol! mY 12 y/o is in a 5 and so are many of the skaters she skates with who are 11! She is in a Competitor boot right now too.

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Do those "kid" boots have the same level of ankle support as the "adult" boots, though?

Looking at the child size 13 Riedell vs the adult size 9 Riedell: yes. Same boot, just a different size. NO indication on websites that the boot differs child to adult; sometimes a missing flex notch, IIRC, on one of the Jacksons way back in the day, but, that was it.

Thanks for the info (I was genuinely interested)

There are physics issues here, even for short and tall people of the same proportions and composition. I may have made some mistakes and incorrect guesses here, but I will try my best to get it right.

As I see it, the height, and the center of gravity with it, all other things being equal, doesn't affect balance, because the body configurations you need to do to stay in balance are exactly the same, unless I just made a mistake. Hence balance is the same. (I ignoring the body mass distribution issues that occur with build and development age.)

But if you fall, the tall person doesn't have as high a strength/weight ratio in structural strength terms (see below). So the tall person needs more fall practice.

However, the tall person has more time to compensate for loss of balance, because the time required to fall to the ice is inversely proportional to the square root of the skater's height. The twice as tall person has sqrt(2)=1.414 times as much time to compensate for imbalance. Don't over-emphasize this - because some of reaction time is nerve conduction time, which is proportional to height.

Both structure strength, and muscle strength, are approximately proportional to cross section area, and therefore to the square of the height. (I am assuming maximum muscle strength is not limited by the number of muscle fibers, but by the strength a person can safely apply without pulling their muscle apart, determined largely by the cross sectional area of the connective tissue in the muscles.

But weight is approximately proportional to volume, and therefore to the cube of the height.

So maximum attainable strength/weight ratios are smaller for tall people. All other things being equal, a twice as tall person would have half the structural and muscle strength/weight ratio.

In reality, strength training can to some extant compensate for weight, by increasing bone density, number of muscle fibers used, and the amount of connective tissue. But the taller, heavier person needs much more strength training to achieve it, and will end up with a stockier build too. Besides, a short person, with comparable strength training, should be able to do the same things. So for the moment assume strength indeed only scales with the square of height, so strength/weight scales inversely with height.

A tall person presumably has a greater distance over which muscle can contract, which I assume to be proportional to muscle length. Since energy available from the muscle scales with strength*(distance over which muscle strength is applied), it scales with the cube of your height. But your weight times your height over the ice is also proportional to energy. So the distance over the ice you can jump is independent of your height.
And your time in the air is also independent of your height.

Now consider spins (on the ice or in the air). Your angular moment of inertia scales with your weight times your horizontal size, which scales with the 4th power of your height. Spin energy is proportional to your moment of inertia times the square of your rate of spin. The energy available is again proportional to the cube of your height. So your rate of spin is proportional to your height to the -3/2 power. The twice as tall person spins at 2 to the (-3/2)=0.3535 times the rate of spin.

So, in the air, you spin a number of rotations proportional to the skater's height to the -3/2 power too. The twice as tall person gets 0.3535 times as many rotations.

All in all, the short person has many advantages, at least for freestyle type moves.

I'm short. For many years I trained about 20 hours/week. I should be an incredibly good skater. Sigh. This suggests that factors like natural talent, the age at which you start training, and how wisely you train, can all be very important too.

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They sure seem to. I'm in Jackson Competitors and they support slightly-overweight me just fine.

Buying "adult" boots isn't an option for me. No one makes them small enough without calling them "kids"

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P.S. Something is wrong with my calculations. Tall people don't get so much fewer rotations in the air. So, tall people must be relatively more fit.

Does that mean just living and moving around functions as strength training?

Should short people dress in fat suits most of the time to get equally fit?

How would that appeal to a typical svelte female figure skater?

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To some extent- yep. Think about basal (I think that's the word) calorie requirements. Large men require many more calories than small women. Just the act of keeping their involuntary organ functions (heart, lungs, brain) going takes more calories than a much smaller person.

Yeah- I got tiny feet (size 5 womens, 4 kids from Lands End- but 3 in Jacksons). I bought them used off an elementary schooler. When she grew out of her next pair- a size 3.5, her Mom offered me those too. I laughed- my feet aren't growing. I don't need bigger boots! I know where my next pair of boots are coming from. I'm just waiting for that kid to outgrow them now

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Too bad custom skates from Klingbeil, the factory/store closest to me, aren't priced the same way!

I wear boys or men's size 6 shoes, if they have wide enough toes. The ones packaged for boys are much cheaper. Likewise for some types of clothing. At my size, stores don't order much, and big boys, small men and many ladies all compete for what is ordered, so I have to visit many stores to find stuff that fits.

A very petite lady of my acquaintance resents not finding adult styles in her size, and is quite sensitive about the issue.

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DD is 5'9" and has always struggled with her height but it does, IMHO, give her the most beautiful line for dancing, as others have said; also everything she does do looks bigger and flashier because there is more of her to see. There is a very small Asian girl at our home rink, not even 5", and her jumps look tiny and are over in a flash because she only needs to get inches off the ice in order to rotate them. DD's flying camel, in particular, and things like footwork sequences and split jumps, just look more impressive when you're that tall (again, IMHO) because there is more there.

I've already agreed to that.

Furthermore, you don't need to be that tall to give the look of long lines. A short skater who is properly stretched with long muscles and lean limbs does just fine. Alissa Czisny has/had no problems giving that look, and she's only 5'4". That has as much to do with form and proper posture/positioning than height.

Makes me want to have somebody film me while I practice ice dance, to see if I look more graceful than I do jumping and spinning.

Since taller people have more weight to carry, and that weight being situated farther away from their core, wouldn't that in itself make them stronger? Having to carry extra weight on three foot long legs up stairs and around town? It would be the effect of putting ankle and vest weights on a short person 24/7..?
(Or am I just rambling thoughtlessly and spewing out untrue theories?)

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Sort of.

Something like bicep curls for example--if you have 2 people, one with shorter limbs and one with longer limbs, and the most weight both of them can do with that exercise is 20 pounds, it takes less strength/energy for the person with shorter limbs to do it than it does for the person with longer limbs because they have less distance to move the weight. So that person with longer limbs is probably, in reality, a little stronger than the shorter person.

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It is sometimes surprising to find out how short a skater really is. When a person is out on the ice alone, there is nothing to give her/him relative size. A 5'4" skater can look really tall depending on body proportions. If the person has a narrow bone structure (rib cage, hips), long limbs, and lean muscles; she will look tall. However, if a skater the same height is stockier (shorter limbs, bigger skeletal structure, bulkier muscles), she will look shorter and heavier. In this case, the stockier skater is probably heavier. Even so, if the hypothetical stocky skater were to stand nx to me, she would look like a peanut. it's all relative.

Kay

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kayskate - you're absolutely right about that. I get fed up with so many people thinking my daughter (4'11" age 11 and after recent massive growth spurt) is a giant. Truth is - she is very, very leggy (also long arms) and has a tiny bone structure. When standing next to one of the "short" skaters it can come as a shock that there isn't a massive height difference - but- short more muscular legs, wider bone structure etc. can make somebody look much shorter than they really are.

Having said that - a 3 1/2 inch growth spurt (since Christmas) hasn't done wonders for her jumps - although spins seem a lot less affected. What has been noticed though is sometimes she has what looks like good technique and something which looks like it should be landed but is followed by a collapse onto the ice. Coaches reckon not always the leg strength to hold onto the landings - so maybe shorter more muscular legs would be desirable!

ITA. My DD had the joy of skating on a session with a number of other tall-ish skaters (5'6" and up) - and didn't look "tall" at all, whereas, on the typical session where she is surrounded by 4'10 to 5"2 - she looks very tall.

Of course, all skaters look small to me when they take their skates off and suddenly shrink 3"!!!!!

I think that's a really good point. And, as someone else pointed out before, the average U.S. ladies' champion is 5'3", which I don't consider that much of a variation from the average height of U.S. women (5'4"). In fact, since most U.S. ladies' champions are teenagers who reached puberty late due to their intense athletic activity, I wouldn't be surprised if some of them grew another inch after winning the championship (I know Mirai Nagasu has). If you look at the average height of female Harvard graduates, you will probably find that it's somewhere around 5'4" also, but that certainly shouldn't discourage girls who are 5'7"!

Huh?? Are you saying a tall skater has an advantage on falls because there is "more time to compensate for loss of balance"? You said a skater's height has no effect on the height of his/her jumps (I'm assuming you mean as measured by the distance between the ice and the skater's feet at the height of the jump). I agree with that, and so would Midori Ito and Evan Lysacek. So that means a tall skater and a short skater are the same distance off the ice during a jump. A fall occurs when a skater loses her balance in the air OR on the landing, becomes misaligned and is unable to keep her feet under her. If the tall and short skaters' feet are the same distance from the ice, how does a tall skater have longer to right herself and catch her balance? If you suffer a bad loss of balance, or you are tilted on a jump landing, or you catch your blade in the ice, you are going to fall unless you have a extremely quick reaction time and sense of balance. Height offers no advantage there.

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You first assumption is flawed. Given two similar objects with the same basic shape but one taller than the other the center of gravity is higher in the taller object. Take to pencils one 2/3 the length of the other find the balance point which should basically be around the center and it becomes obvious that the center of mass is lower in the shorter pencil if they were both placed on end on a flat surface.

Applying this to two skaters with the same basic build if the center of gravity for both skaters is somewhere around their midsection the smaller skaters center of gravitiy will be lower as their mid section is lower to the ground.

Therefore balance is not the same, advantage short skater.

That's funny about the mom! I am a short person(5 ft 1) and my feet are a size 7.5-8! My mom is a taller woman(5 ft 7) and until she broke her foot, she could fit into a size 6.5-7. Now she wears a 7-7.5. My daughter likely will not be a tall woman. She is 12 now and is around 4 ft 10 and wears a size 5 skate and can wear a 4.5-5 in kids shoes and about a size 6-6.5 in womens(depends on the shoe). Funny thing about dd tho. People see her on the ice and THINK she is tall for her age, but she isn't! She is short and tiny(weighs maybe 75 pounds)! She has LONG legs, so when people see her skate, they assume she is tall! She'll be lucky to be 5 ft 4! Funny, huh?

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I agree that the center of gravity is lower - but it scales with your height. So unless my thought process is flawed, this means that most of the differences in balance that come from internal forces and gravity are very small. Specifically:

Balance is essentially the same in that the conditions for both static and dynamic balance are not altered, in terms of the static and dynamic poses and horizontal motions that leave you in balance. I.e., you are in balance if your center of gravity is over your base of support, taking into account inertial forces for dynamic balance.

There is a very slight change because inertial forces do not act quite the same way as gravitational forces. That difference on the order of the difference between the center of mass and the center of gravity - insignificant for human sized skaters. It matters when skyscraper sized skaters like King Kong skate, because gravity is less powerful at the head.

It is true that vertical inertial forces do not entirely scale with height, because of the interaction with gravity and centrifugal force from the spin of the earth. This affects dynamic but not static balance somewhat. For example, if a tall and short person drop at free fall rates, the fall rates are not the same in that they do not scale with your height.

Hence, what happens if you go out of balance does differ, in that the motions you go through as a result of imbalance are slower, in relation to the size of the person, for the taller person. The advantage is to tall folk, because they have more time to react.

Horizontal Coriolis forces differ too, but I doubt that is particularly significant. After all, we don't commonly worry about compensating for the difference between skating from low to high latitude vs high to low latitude, or between skating in the direction of the earth's spin vs against it.

Air resistance forces are somewhat different, and do not scale with the weight of the skater. That mostly matters at high speeds. The shorter person gets proportionately more wind force. (That is part of why bumblebees need not be shaped like eagles.)

If the tall folk are adults, and the short folk are kids, the kids have many advantages, because their center of gravity is on average lower, relative to their height, and their reaction times are shorter - but I started with the assumption that shape and composition were the same.

Skaters are not buildings. I.e., we are not anchored to the ice. Nor, except for the aforementioned air resistance at high speeds, do we need to worry about wind sheer or earthquakes. Buildings are much more stable when they are low, because of these external forces.

I'm not that sure about the horizontal forces from the ice. That is an external force too - and I'm not sure it is proportional to your weight.

But overall, balance is still pretty much the same.

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No. Balance isn't pretty much the same.

I disagree with this. I am 6' tall. When I tilt my shoulder 1 inch out of line, the resulting error is worse (and therefore harder to compensate for or fix) than if a 5' tall girl was 1 inch out of line--if you drew a vertical line straight up from the blade (contact point w/ the ice), my shoulder will be farther out of line than the shorter person's. I'm no physicist (obviously) & I'm not saying it quite right, but the point is that even my small errors are bigger than the exact same error on a shorter person.

Exactly what I said earlier in the thread, in my Ruh/Cohen example, so I have to agree with Phoenix.

Phoenix is correct, the issue isn't when you are in balance it is when you get out of balance and have to correct ie. your stability. For a taller skater the same degree of error off axis is much harder to correct that for a shorter skater. My DS who is about 6'1" has to work much harder that his 4'10" partner to correct an off axis jump or spin.

Also the energy required to put a object out of balance is lower for a taller object assuming everything else is equal as the center of gravity is higher in the taller object. Also the amount of energy required to put the out of balance object back into equalibrium is higher for the object with the higher center of gravity.