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The Double Axel Barrier… And Female Athlete Vertical Jump Statistics

November 7, 2007

As my loyal readers know, I’m very interested in understanding the athletic and physical limits associated with figure skating jumps, particularly for female skaters.

One of my goals is to understand what percentage of the female population has the athletic ability to do a double axel.  As I’ve shown before, the double axel is a huge dividing line for most skaters.

The next hardest jump, the double lutz only needs about 0.36 to 0.38 seconds of flight time based on video analysis (using Dartfish and simlar programs).  I’ve actually measured flight times on clean double lutzes as low as 0.34 seconds.  But using the 0.38 second number and using the table in a previous post on this blog (Are Figure Skaters Projectiles?), the double lutz needs to be about 6.5 inches high.

The double axel needs to have about 0.467 seconds of flight time, although I have measured ones with as little as 0.45 seconds.  Using 0.467 and the jump height chart gives about 10.5 inches as the minimum height for a double axel.

So why is this so important?

Mainly because based on my observations, most female figure skaters cannot jump 10.5 inches off the ice.  They just don’t have the physical ability to jump that high off one leg, regardless of technique.

To understand what I’m talking about, here’s an example.  Consider an ‘average’ 13 year old female skater.  According to the statistics, an average 13 year old female can jump 11.5 inches vertically off two feet.  This distance includes the ankle extension while still on the ground.  Estimating the distance of the ankle extension as 2.5 inches, that makes the true vertical “jump” or vertical distance in the air for the average 13 year old female only 9 inches.

And remember, that’s off two feet.

What are the statistics for one foot?  I’ve been unable to find any statistics on this so I’m running a study to determine this number so I can correlate it with the existing data.

But for the sake of argument, let’s say a skater can only jump 80% as high off one leg as off two.  That gives the average 13 year old female a potential jump height of 7.2 inches (0.8 x 9 inches = 7.2 inches).

And since a double lutz needs to be only 6.5 inches high, the average 13 year old lady skater clearly has the physical ability to do it.

So if the assumptions are reasonably close, we can see why most female skaters with average athletic ability or above can get through double lutz.  But we can also see why average female athletes have no chance at a double axel.  Their vertical jump off one leg is nowhere near the required 10.5 inches.

OK, just for illustration purposes, based on the assumptions above (2.5 inch ankle extension, 80% height off one leg), how good of an athlete does a 13 year old lady need to be for double axel?

If the jump needs to be 10.5 inches high and the ankle extension is 2.5 inches the skater needs a vertical jump off one leg from a standing position of 13 inches (10.5 + 2.5 = 13).  If the 13 inches are off one leg, then the skater needs to jump 16.2 inches off two legs (13 / 0.8 = 16.25).

According to available statistics, a 13 year old girl that can jump 16. 2 inches off two legs is in 97th percentile.  That means that only 3% of this age group can jump higher.

Wow!  Guess what that means?

If all the assumptions were reasonably close, only 3 percent of 13 year olds ladies have the athletic ability to jump high enough to do a double axel.  Now I’m sure this number is too low but it illustrates my point.

It should be clear why so few female skaters get a double axel.

OK, just for completeness I need to be very clear here.  I pulled the 80% number out of thin air.  And the 2.5 inch ankle extension number is a conservative estimate based on a handful of measurements ranging from 2.25 to 3.5 inches.  But these numbers need to be investigated.  And I plan to do that as part of my vertical jump study.

Also, the vertical jump numbers for 13 year old females was determined using an Online Vertical Jump Calculator.  And as elite skating coaches will confirm, a skater can actually jump higher on the ice with good technique due to the ability to use the speed of jump entry to vault the jump upward.

In other words, there’s a lot of assumptions here that need to be investigated further.

I hope you find this information useful.  As coaches, we need to stop having our skaters attempt jumps that they don’t have the vertical jump ability for and they simply have no chance of landing.

Trevor

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22 comments

  1. I very much appreciate this point

    “As coaches, we need to stop having our skaters attempt jumps that they don’t have the vertical jump ability for and they simply have no chance of landing.”

    I am a 40 year old former child skater with scar tissue from falling on double lutzes (which I eventually got) and double axels that I never got. It was a source of great humiliation to me to wear crash pads and be pushed for something that other skaters were doing with ease (I trained at the same rink with Laura Steele who back in the day was a jumping bean extraordinaire-same age as me and way more talent) Biomechanically I think it was just impossible and its sad that my coach and parents didn’t know any better. I’m really looking forward to needing a hip replacement or having arthritis from that trauma in another 20 years…

    Parents and coaches must understand that wishful thinking cannot override the laws of physics and practicing isn’t going to make it happen. Girls should have plyometric training and this type of testing done to confirm readiness before they even think about trying a double axel or a triple.


  2. […] Coaching Weblog A Day In The Life Of A Figure Skating Coach…With A Computer « The Double Axel Barrier… And Female Athlete Vertical Jump Statistics Initial Test Of Vertical Jump Measurement Methods November 18, 2007 Continuing the […]


  3. First off, in any sport, as you climb higher up the ranks (whatever they are at the time) less and less athletes (female or male) are able to perform the required elements. That’s what makes them competitive and elite.

    However, saying that a portion of the female population is just not capable, no matter what, of landing a double axel is ridiculous.

    I have a plethora of problems with your methodology and assumptions:

    – you are comparing apples and oranges. your statistics are for “average 13 yr old female” and “average 13 year old female figure skater.” Perhaps only 3% of the female population can reach the vertical jump height; however, what percentage of females are figure skaters and what percentage of female 13 year old figure skaters can attain the height? It is likely, given their training, that the average 13 year old female figure skater has a much higher vertical jump than the average 13 year old female non-figure skater.
    – you are not taking height, weight, or shape into account at all. I would assume that a smaller 13 year old can rotate faster than a taller or heavier or more developed 13 year old in which case the amount of time necessary in the air would decrease (and thus less vertical height is necessary)
    – when talking about the double axel barrier (which I believe there is), you are assuming that ALL of the reason is the athletic ability of the skater. However, let’s assume that most female skaters begin double axels around 13 – this is also the age when school is getting more intense, social pressures are increasing, and, perhaps more importantly, their bodies are changing. It’s also likely that they may be changing coaches/locations to be more competitive. A comprehensive study of the subject MUST take these external factors as well as athletic ability and training (how often are they skating, what off ice conditioning are they doing, etc)
    – I’d also note that in moving from recreational to competitive skating, the single axel is definitely a barrier which may imply that there is something about the axel itself that it physically difficult/unnatural for everyone (the forward take-off? the extra 1/2 rotation?)

    I, personally, think searching futilely in quasi-science and coming to conclusions about the innate ability of your skaters (perhaps to hide your own inadequacies?), is not the way to ‘better’ yourself as a coach.


  4. I’ve been training this skater off-ice for almost a year now as well as well as conditioning her. She’s currently starting to learn her double axel and is having quite a hard time landing it even with the harness. Regarding your estimation of jumping with one leg would be 80% as high as jumping with both legs might not be true. Try looking for basketball statistics and you’ll see that most of the time they could jump higher using one leg than using both legs. I find it true for myself as well… just a thought


  5. It seems like you have not consider adding in the momentum.


  6. I have always been looking for such post. Thanks for the info!


  7. Great post. While I understands the criticisms, it’s important to understand that the normative standards for this are non-existant. If the ISU (or someone else) actually funded/conducted such a study in the first place, there would be no need for ‘lay practitioners’ to scientifically attempt to explore this.

    Figure skating has to catch up with the times…


  8. Hi Trevor

    I find your site so very interesting. Came across it as my daughter is about to start learning double axel but I am concerned she is too young and i fear her ankles may not be strong enough. Although I have noticed that it seems easier for the lighter younger skaters to attampt some jumps and from research I see it is because of the narrowness of their hips.

    She is 9 years and 9 months old.She has all her doubles nice and consistent. The double lutz is not fully rotated but strangely enough has had less trouble with it than some of the other doubles.

    Here is my question. Do dont mention rotational speed when discussing the double axel only height. Surely a greater rotational speed means the jump does not have to be as high ? I am sure girls who jump high but rotate slowly will battle.

    Lara has a very fast rotation and perhaps its why she has managed her doubles so well . But because the rotational speed is so fast she has not worked on height and I would very much like to see more height in her jumps. We are working on having a higher jump withless pull in so that the height is there when she needs it for double axel. I am also nervous to slow her rotational speed down cause she needs it for triples and double axel. What are your suggestions.

    I look forward to your replu

    Regards
    Ashley


  9. […] ·        TheDouble Axel Barrier… And Female Athlete Vertical Jump … – I very muchappreciate this point. “As coaches, we need to stop having our skaters attemptjumps that they don't have the vertical jump ability for and they simply haveno chance of landing.” I am a 40 year old former child … […]


  10. i was looking for tips on double axel… not discouragement…


  11. Haha so how come at least 20-30 13 year old girls in intermediate at JN’s do it every year.


  12. In reply to Mister: The skaters you refer to at JN’s are almost always the best athletes in the entire nation, many with a specific body type that allows them to jump high and rotate fast. My post above emphasizes that the average female athlete probably does not possess the ability to ever land a double axel. I recently attended JN’s and did some informal vertical jump testing and found that in general, the athletes at JN’s are well above average in terms of physical ability. Thanks for your post.


  13. I seem to remember Michelle Kwan jumping without a lot of height- yet she had the double axel and all of her triples. I remember thinking her jumps were very tidy and looked like they had perfect technique- they just weren’t very high…


  14. Yes Skating Fan, Michelle Kwan had a very efficient double axel that was not very high, but it did have more airtime than the common minimum of 0.45 seconds. Thanks for the input.


  15. Awesome article, my triple loop is about 14 inches.


    • Thanks for sharing Laura. 14 inches is roughly 0.53 to 0.55 seconds of air time which certainly matches the requirements for a triple loop. I’ve seen a few triple loops at 0.51 seconds but most over 0.53. You’re obviously a very good athlete.


  16. This was a very interesting analysis. I personally believe that training of figure skating does need to be a little scientific and use of today’s technology is a wonderful tool. There are times when skaters need to work certain physical abilities off skates and target areas of weakness. Another aspect of this is body frame. Obviously, a muscular 6 foot tall 200 lb man would have a hard time rotating fast, but there are some this size that do triples because they get up very high. In the early 80s there was a roller skater this size named Rick Elsworth (he’s on YouTube) who could do a triple Lutz. And roller skates weigh 4 lbs each.


  17. While I appreciate your scientific approach to skating and greatly believe in the effectiveness of video analysis, I think asking coaches to dash the hopes and aspirations of their skaters based on numbers is foolhardy.

    This sport has suffered from a long-time epidemic of false beliefs that have prevented many from achieving greatness.

    This sport has suffered from too many limitations and a failure to allow development that truly gives life to performances, or gives the individual a positive message. Younger is better, slimmer is better, faster is better.

    Where is the progress?

    Yes, you need jumps to be competitive, that is not at question. But disqualifying an athlete before they even have a proper chance to develop fully is not right.

    Coaches, please remember to encourage. That can be the difference between greatness and failure.


  18. Thank you for your input SJ. I agree we want all coaches to have a positive message and be encouraging. But many coaches are “so positive” that they risk the health and safety of their skaters by asking them to try jumps that they are not yet ready for.

    Note that I did not say we should not help those skaters find ways to become ready to attempt difficult elements. A coach’s job is to get the skater ready and provide honest and realistic feedback to help the skater achieve the next step in their development. Encouragement helps the skater stay motivated.

    Blindly encouraging a skater to try double axels without assessing the situation first properly is generally not beneficial. And looking at jump air time is one very specific way to do it.

    As it turns out, some of the greatest skaters of all time had extremely negative coaching. So the idea that the difference between greatness and failure being a result of an encouraging coach is simply not generally valid.

    I promote positive coaching and encouragement because it develops the skater’s self esteem, not because it makes them a better skater or a champion. It’s been demonstrated repeatedly that a champion can be created using brutal and damaging methods.

    Being truthful with skaters about physical limitations is not “being negative.” Instead if offers insights about what training methods and requirements are needed to reach the next performance level.


  19. Thank you for attempting to measure this. As a scientist and a figure skating athlete, I appreciate this approach that is built on rational analysis. Physics is physics. It is not “negativity” or “discouragement.” Of course, it is always possible to use plyometrics, weight training and other methods to improve jump height. This helped me a lot. I am very surprised that the jump height requirements are so low! I can jump higher than 16″ off one foot. But, I am a 5’9″ 127 lb, 43-yr-old female skater and not some petite child.


  20. This was a very interesting read. My child (11 yrs old) is working on the double axel and has a vertical jump just shy of 18 inches. Right now after about 11 weeks the jump is rotated but the checkout is rough. There are several at the rink who have been trying the “DA” for over 18 months to no avail until they began a plyometrics regimen. Not wanting the same frustrations we opted for plyo training twice a week and strength/conditioning once a weak. This regimen will continue for 6 to 8 weeks and then retest the vertical jump.

    The reason I believe in your theory is because one year ago my child was only doing an axel in competition but now has a double lutz and double flip combo in the program.

    Keep up the research,

    Thanks


  21. Update: vertical is now 23 inches and the DA has been landed. Triple sal has been fully rotated but checkout needs some work.



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