Archive for the ‘Axel’ Category

h1

Figure Skating Jumps – A Review of Minimum Air Times (Trevor Laak)

July 2, 2014

With the prevalence of low cost video analysis apps on mobile phones and tablet computers, video analysis of figure skating jumps is within reach of EVERY coach and skater. Past research into minimum air times for each jump can now be used by all figure skating participants to help assess skater progress and minimize injuries.

To my knowledge, no formal publication of jump minimum air times has yet been made. However, a large number of researchers including this author have compiled statistics on minimum air times that should provide helpful guidelines for those interested.

I have received a huge number of requests for this information so I hope this post addresses the interest in this topic.

 

Why Minimum Air Times Are Important

Knowledge of minimum air times is important to coaches because it provides a relatively clear way of assessing a skater’s athletic progress and technical progress with any given jump. If a skater is matching or exceeding the minimum air time for the jump and has solid technique and an appropriate body type, they should be able to get close to full rotation of the jump under ideal conditions.

Air time information serves two important and related purposes in the development of figure skating jumps.

1. It reduces the pressure on skaters to complete elements that they physically have no chance of completing, and

2. It dramatically minimizes injuries from attempting jumps a skater is not yet ready to attempt.

Skaters have historically been under extreme pressure to land more advanced jumps at younger and younger ages. As the sport progresses technically, this pressure is only continuing to grow.

How many skaters feel guilty about not landing their double axel (or any jump) after working on it for months or years? Skaters often feel that they are letting their parents and coaches down and they often experience extreme frustration at themselves for not learning a new jump sooner.

But minimum air time measurements can help to reduce this guilt and frustration. If a skater knows she or he is not jumping high enough to land a jump cleanly, the focus turns to solving that problem rather than remaining fixated on just landing the jump.

Similarly, coaches can help their skaters dramatically reduce injuries by knowing their skaters’ air times and not expecting or demanding that the skater stand up and land the jump when they are simply not ready. It then becomes the coach’s job to help the skater optimize jump technique and develop the necessary jump height through off-ice training.

The days of repeated futile jump attempts are over, or at least they should be. In this day and age, no coach should continue to apply the just-stand-up-and-land-it mentality without knowing air times.

How These Numbers Were Generated

The minimum air time numbers for each of the major figure skating jumps provided below were compiled from measurements of many jumps over a long period of time. By measuring air time on as many jumps as possible over a period of many years, certain air times stand out for each jump.

Some of the measurements were made on practice jumps videoed directly by a coach or skating parent while others are a result of digitizing televised broadcasts of competitions or other events of elite skaters. Historically, a televised skating competition or event could be recorded and then digitized to provide model jumps for analysis.

 

Caution With The Numbers

It should be noted that attaining minimum air time does not automatically mean a skater should be able to land a given jump. Minimum air times are typically only possible by skaters with extremely efficient technique and an optimal body type.

Skater body type plays a big role as smaller and thinner skaters typically have an advantage for faster rotation. Even this is an over-generalization because some tall skaters can rotate very fast, but as a general rule, it is small and thin skaters that these minimum air time numbers were generated from.

Thus, larger skaters or those that have a more substantial frame will almost always need more than the minimum air times listed below.

Rotation rates are obviously also affected by take-off mechanics. This means that a skater may jump higher than the minimum air time but lack the ability to create enough rotational energy on the take-off to spin fast enough in the air, even with a perfect air position and body type.

Coaches should strive to help their skaters optimize jump take-off technique and air position. Jump height is a result of jump technique as well, but overall skater athleticism appears to have a very strong influence on the ability to jump high. The development of athleticism is probably best attained through significant focus on off-ice training methods.

For more information about jump technique or off-ice training methods, please visit iCoachSkating.com. That website is committed to providing the best educational information on the nuts and bolts of how to figure skate.  It has literally hundreds of videos on jump technique from some of the world’s best coaches.

 

How to Measure Air Time

For accuracy, it’s important to maintain correct measurement methods. When analyzing jump air time, the measurement should be made from the first video frame a skater’s blade is in the air to the first frame the skater’s blade touches the ice.

It is NOT accurate to measure from the last frame on the ice to the first frame back on the ice. This measurement method will result in air time measurement that are too large. The details of this are beyond the scope of this article and will be provided elsewhere.

Simply use first-frame-off-the-ice to first-frame-on-the-ice and you’ll be fine. Most apps don’t have a way to reset the clock to zero on the first frame in the air, so record the time at the first frame in the air and the first frame back on the ice and subtract to get air time.

 

Shout Out to Christy Krall

At the 2011 PSA World Conference in Dallas, TX, World and Olympic figure skating coach and video analysis expert Christy Krall gave a presentation in which she provided insights about minimum air times for all the main jumps from double loop through triple lutz. To my knowledge, Christy has not published these findings elsewhere, partly since she uses these only as guidelines and there may be some skaters with successful jumps at lower air times.

I am publishing both Christy’s numbers and my own observations here for your reference. But remember, these numbers only represent our experience and are not absolute. Christy provided numbers for both male and female skaters (female/male). Air times are provided in seconds.

Jump                     Trevor                   Christy
Abbrev.               Air Time                Air Time

1A                           0.30

2S                           0.30

2T                           0.30

2Lo                         0.33                        0.35

2F                           0.35                        0.35

2Lz                          0.35                        0.35+/0.36

2A                           0.45                        0.45/0.47-0.51

3S                           0.47                        0.47/0.48-0.51

3T                           0.48                        0.47+/0.48-0.51

3Lo                         0.50                        0.51/0.52-0.53

3F                           0.53                        0.53+/0.56-0.58

3Lz                          0.53                        0.53+/0.56-0.58

3A                           0.60-0.62

4S                           0.63

4T                           0.63

 

These Minimums Are Not Absolute

Again, these numbers are not absolute. For example, I’ve seen 2 double axels with an air time of only 0.43 seconds. One was during practice sessions with a young skater in Korea with extremely efficient technique and a very thin body type and the other was off video taken by another coach of a similar Japanese skater who eventually became a World Champion. I do not consider 0.43 seconds to be a reasonable minimum air time for double axel because my experience shows that only an extremely rare and talented skater can pull it off.

Similarly, Sasha Cohen was capable of landing a quad salchow with just 0.60 seconds of air time. This astonishing feat of optimization may represent the absolute lowest possible air time for quad salchow, but most quad salchows are being landed with air times of 0.65 and higher. A significant number of skaters have landed the quad salchow at 0.63 seconds which is why it’s listed on the chart as the “reasonable” minimum.

When we use minimum air times with our skaters, we want them to target a reasonable number for their body type. So based on the skater’s body type and my experience, I may shift the numbers slightly so they have a more appropriate air time goal. We want skaters focused on meeting and exceeding air times that should provide success.

I hope this article is helpful. I did not ask Christy for permission to publish her air time numbers here but felt that her work deserves your awareness. Her groundbreaking research was a starting point for my own observations and this article would not be possible without her contributions.

 

Final Note

To get an idea of what these air times mean in regards to actual jump height, please see my previous post comparing air times with projectile height (Are Figure Skaters Projectiles?).  Sometimes it’s helpful for skaters to understand how much more jump height they need. Knowing that your double axel air time is 0.40 seconds and you need 0.45 seconds is somewhat abstract. But knowing you need to generate an additional 2 inches of jump height is very tangible to most skaters.

Please leave a comment and let me know if this article was beneficial.

h1

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

h1

Figure Skating Coaches Need Discipline

November 2, 2007

I wanted to make a comment about how much discipline and patience we need as skating coaches.

Today I worked with a low-level skater on a her scratch spin.  I work with this skater in private lessons on a fairly regular basis.  This skater is currently in a basic skills program and is learning a scratch spin in her class.  But I’ve been very unhappy with the technique she’s been learning in class.

Unfortunately, she’d been having some success with the poor technique, spinning about 3 fairly centered rotations.  What I disliked about her technique was she was taught to simply twist into the spin, while I wanted her to glide on a long entrance edge to allow longer, faster spins.

This put me in an awkward position.  I had to convince her to try it my way without openly criticizing her basic skills instruction.  Not surprisingly, when she initially tried it my way the results were terrible because she could not control the entrance edge.  It took multiple lessons over several weeks of patiently and gently demanding the technique I wanted before she started to “get it.”

And today was the breakthrough!  Today she could finally control the edge as it got deeper and deeper until the edge naturally turned into a spin.  Her spins today were nearly centered and she was now getting 6 full revolutions.

With today’s success, I could see that she finally “bought into” the technique I was teaching her.  Up until today, she was merely humoring me.  She was willing to try what I asked, even though it wasn’t working, because I remained utterly unshakable in my requests.  This is the discipline I’m talking about.  We need the discipline to ask a skater to do the proper technique every single time.

Too often I see coaches throw away a valuable 15 minute lesson of technically improving drills by giving in to the skater’s desire to try the element when they’re still not ready.  Often coaches are giving in to their own curiosity or lack of patience.

I once took away a skater’s axel for 3 months.  At the time, she couldn’t get her free leg in front before jumping.  We used the three months working on exercises to slowly and persistently change her technique.  By the end of the three months, her new technique was totally ingrained in muscle memory.  Her technique was fixed from the very first axel she tried after the 3 months.  And it was permanently fixed!

As coaches, it’s our job to be patient and make sure the technique is good.  Skaters rarely have any patience.  And their parents are usually even worse.  As coaches, we’re the only voice of reason in the process.  The problem is, as coaches we’re likely to give in to our own curiosity, the skater’s pleading, and the parent’s pressure.

Stay strong!

Trevor

h1

Why Computer Analysis And Not Just Slo-Motion?

August 27, 2007

One 0f the main uses of video analysis software with figure skaters is determining flight times.  Why?  Because flight time or jump height largely determines jump success.  For example, based on all the video that I have analyzed, I have never seen a double axel that had less than 0.467 seconds of flight time.  And other video analysis experts have confirmed this value.

Dartfish experts Chris Conte and Audrey Weisiger use a value of 0.500 seconds for double axel.  But I have personally measured a handful of double axels at 0.467 and in fact, one of the skaters I work with regularly in Madison lands it consistently with that flight time.  But she is very slender and has an awesome rotation rate.  So most skaters that are not as slender will probably have to meet Chris and Audrey’s 0.500 second minimum.

If a skater is ready to work on double axel but cannot perform a single axel with at least 0.467 seconds of flight time, she should spend nearly 100% of her effort making her jump bigger.  The chances are simply not good that she will be the first skater ever to land a double axel with less than 0.467 seconds of flight time.

This feature of video analysis software truly sets computer jump analysis apart from basic slow-motion video analysis.  Of course, basic slo-motion has been used by coaches for years and is very common in figure skating.  But computer analysis provides flight time and takes coaching to another level.  Knowing the flight time of the jump is critical for understanding what is possible.

All the time, I see skaters that are attempting double axels and triples that simply do not have the height necessary to land those jumps.  And unfortunately, they continue to practice them over and over, teaching themselves to fall or teaching themselves to land cheated jumps.  Since their coaches don’t realize they will never land it without more height, they keep doing it, and ingraining an incorrect movement that can be nearly impossible to change.

And that largely explains why double axel separates the really good skaters from the rest.  At the recent Frank Carroll  workshop in Milwaukee, Mr. Carroll described skaters having jumps and jump combinations through double lutz as being very good… but skaters with a double axel are in another class.

And that’s also evident in some surveys I’ve done.  Many coaches rarely get the chance to work on double axel.  And when they do, they are almost never successful.  The percentage of ladies that actually learn to do it consistently is very small indeed.  And no wonder… just getting any female athlete to jump 10.5 inches off one leg is quite a feat! (10.5 inches represents 0.467 seconds of flight time based on projectile motion calculations… more about that in a future post!)

And here’s some more astonishing but useful numbers.  Minimum flight time for double lutz is about 0.366 seconds.  That makes the difference in flight time between double axel and double lutz just 0.1 seconds.  But guess what?  Those 0.1 seconds represents a whole 4 inches!!!  So you can do a double lutz with just 6.5 inches of height but you have to jump over 60% higher to land a double axel!  No wonder so many skaters never get one…

If you have skaters working on double axel, do yourself and them a favor by getting a computer analysis done.  Find someone to help you if you don’t have the tools yourself.  The bottom line is – computer video analysis is truly a major leap forward in figure skating coaching for advanced skaters. 

Trevor

h1

Example Dartfish Analysis of Figure Skating Jumps

August 14, 2007

I did a Google search today for examples of figure skating elements that were analyzed using Dartfish.  Dartfish is a video analysis program that has been around for many years but is expensive and therefore beyond the reach of most skating coaches.  Still, I know of at least 22 figure skating coaches currently using Dartfish on a regular basis.

So why aren’t there any example analyses available online?

Well, now there is.  To see an example of a Dartfish analysis performed by Chris Conte (of a double axel), check out the Skating Coach Quiz.  This is a classic example of how Dartfish and other video analysis programs can be used to speed the training of skaters.

Tomorrow I’m attending a Frank Carroll workshop at the Petit Center near Milwaukee, WI.  I’m looking forward to learning a few things.

Trevor

h1

Inconsistent Axels May Be Lacking Airtime

August 13, 2007

Today was a routine day at the rink.  No breakthroughs.  Some skaters are stressing about the upcoming DuPage Open competition this weekend.  It’s also time to decide exactly who is ready to test at the upcoming test session here in the Madison area.

One of the skaters I work with regularly was upset today because she wasn’t landing her double toe and the technical changes I suggested made it “feel” worse.  This is so common in coaching that I felt it deserved a comment here.  I find myself constantly repeating to my skaters that to learn a new skill, there’s a good chance they’ll have to get out of their “comfort zone.”  As obvious as this sounds to many of us, it is not obvious to our skaters.  Especially if they have landed the jump in question before.  But we know that this is true with anything…without stretching ourselves, we wouldn’t grow.  And there’s discomfort in stretching ourselves.

Anyway, today’s video analysis is another axel.  Click the link below to see one common problem that reduces axel flight time and the effect it can have.

 Common Axel Flight Time Problem

If you find these videos helpful, please post a comment below.  Thanks.

Trevor

h1

Figure Skating Video Analysis Example

August 13, 2007

Today I spent a few minutes creating a short video analysis of an axel attempt.  If you look closely, you’ll notice there is no Dartfish symbol on the final video.  The reason is that I do not use Dartfish for my video analysis.

 Of course Dartfish is the industry standard at this time, but considering the cost (>$1500), it just isn’t practical for the majority of figure skating coaches.  Ialready owned a medium cost laptop produced in early 2006 and an inexpensive digital video camera, and created a full video analysis system for less than $300.  I’ll reveal how I did it in a future entry.

 To see today’s analysis, click the link below:

Axel Two Foot Landing Video Analysis

 The video shows clearly one of the major errors that many skaters have when learning the axel.  The error is usually caused by fear as described in the video. 

Please comment on the video and let me know what you think of it.

Trevor

P.S. Don’t forget to check out Skating Coach Quiz!  There’s a great Dartfish analysis performed by Chris Conte you should really see. 

Figure Skating Video Analysis Rocks!