The Double Axel Barrier… And Female Athlete Vertical Jump Statistics

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