8 minute read
The Blink of an Eye
Is the Rate of Rotation Exceeding What the Naked Eye Can See?
By Kent McDill
When Nathan Chen began landing quad jumps, and when Ilia Malinin landed the first quad axel in competition in the U.S. Classic in Lake Placid in 2022, the figure skating world collectively existed in awe of what had been accomplished by the human body in motion.
The physical effort involved in making that many rotations in a single jump is difficult to fully comprehend. Such jumps are also incredibly challenging to actually see and measure— in detail!—via the human eye. And now? Skaters are working on quint jumps.
There are 1,800 degrees of rotation per second in a quadruple axle.
“The quadruple jump was previously considered as an unrealistic thing for human beings, but the fact that so many skaters hit it almost naturally means somebody will land a quintuple someday,’’ said Olympic medalist Shoma Umo back in 2019.
And what do judges think about that possibility—from a technical standpoint?
“Can the human eye actually decipher the five rotations?’’ asked Professional Skaters Association Hall of Fame technical judge Gale Tanger. “We have reached the human capacity to evaluate that.”
A solution to the problem lies in the use of video replay to assist in judging. Video replay technology has been adopted by most professional sports around the world. But the speed involved in figure skating jump rotations is unique in its visual complexity, and there are even limitations to what video replay can offer in determining just what has happened in that less than a second the skater is in the air.
This problem has no simple resolution and there is no consensus on which available solution is the best for the needs of technical panels or judges.
Technical Difficulties
At the turn of the century, following the judging scandal that occurred at the 2002 Winter Olympics, the International Skating Union added video review to the process of scoring major events. It was first employed internationally at the 2006 Winter Olympics. There are three advantages to video review. The first is the ability of judges to view a jump for a second time just to be certain of their scoring on technical elements. The second is the ability to view a jump in slow motion. The third is the ability to pause a video for specific moments in the performance.
However, skating competitions today are using relatively basic video equipment, similar to what exists on current smartphones. For the purposes of judging jumps that include 4-4.5 rotations, such video equipment is not sufficient. Also, many competitions today employ just one camera, and one video viewpoint is not considered adequate for the needs of technical judges who wish to determine the quality of specific elements within the jump.
“I think they miss quite a bit if they use a regular video camera and use only one,’’ said Lee Cabell, the renowned figure skating coach with an educational background in biomechanics.
“When identifying an element, it comes back to reviewing that element and coming up with conclusions,’’ said Mitch Moyer, the senior advisor for U.S. Figure Skating who previously served as Senior Director of Athletic High Performance. “The bottom line is the equipment they are using is not sufficient to make that call.”
Unfortunately, the answer is not necessarily investing in higher-speed cameras. Beyond the cost factor involved, higherspeed cameras capture more frames of reference per second but lose resolution when used in slow motion replays.
Add to that the concern over the amount of time it takes to review more frames per second than what is currently offered (ask Major League Baseball about its issues related to video review timing), and you have a conundrum.
There is another solution, which will be introduced later, after we consider the mathematics of video review versus human eye consumption
"I Was Told There Would Be No Math"
Today’s mathematics lesson regards the ability of the human eye to compute what is being seen. So it becomes a biomechanical lesson as well.
Cabell explains that the visual presentation of a quad axle, which actually includes 4.5 rotations from takeoff to landing, offers 5 hertz, a hertz being a unit of measurement equivalent to one event per second. Anatomy books will tell you the human eye can see 60 hertz of light, and 75 hertz of motion. As Cabell explains, “The being used.
The video cameras being employed in current competitions record 30 frames per second. As Cabell explains, there are 1,800 degrees of rotation per second in a quadruple axle. That means each frame of video being reviewed is “seeing” 600 degrees of rotation.
‘I don't know how judges can do this,’’ Cabell said.
“It is impossible to do what they are doing with what they have,’’ Moyer said.
As Cabell explains, when looking at a performance frame by frame with the equipment currently being used, the foot is in one position in an initial frame and then moved 60 degrees further in the second frame. Much is lost in between frames 1 and 2.
“With video review, we are basically taking frame by frame, and you still have gaps,’’ Moyer said.
Obviously, the answer then is to acquire video equipment that operates at a higher speed, offering more frames per second, similar to the VAR (Video Assistant Referee) cameras used in soccer matches.
The bottom line is the equipment they are using is not sufficient to make that call.
The cameras used in soccer measure 50 frames per second, and are often used to judge to determine whether a jump is over- or under-rotated, high speed video would be preferred.
Rotation is one aspect of a technical judge’s job. Another is footwork, and Moyer points out that judging footwork via video review takes time, and time is of the essence in announcing competition results.
“Judging with high speed camera review will slow down the event,’’ Moyer said. “I don’t want to be judging footwork at 240 frames per second.”
That’s a lot of frames. Reviewing lots of frames of video takes time, and time is a matter of concern when it comes to the execution of judging in major competitions.
"It’s got to be a good experience for the fans and the athlete,’’ Moyer said. “When you are getting to the point where the human eye can’t see it and you are using a video, that is slowing down the process. We have drastically reduced the time it has taken, however. It used to be a lot worse. It would go on forever.”
An Easier Solution
Moving over to the other most popular winter sport, skiing, we find that skiing coaches are using wearable sensors to measure body positions for ski jumpers in motion. A similar technology could be used with figure skaters to allow for an accurate measure of where, how and when a skater’s skate touches down. Sensors could be placed on the skate blade, for example. The possibilities for sensor measurements in figure skating scoring are vast.
Figure skating coaches are now using sensors to measure training loads. They can be used to create a 3D model of a skater’s rotation for study.
A great idea, right? There is a concern, however, with the use of sensors for use in judging. A sensor could be programmed to provide very specific information about a jump, which could, in unpopular theory, replace the technical panel altogether.
Anyone with an active fear of artificial intelligence taking over all of our jobs can understand the concern.
“From an AI perspective, sensors could be useful for a technical specialist to identify what is and what isn’t,’’ Moyer said. “Let’s call it ‘helping them’.”
Quantitative vs. Qualitative
The issue of judging 4- to 4.5-rotation jumps for technical execution does not impact the judging of the qualitative, artistic aspect of figure skating judging. For someone who has lived through the evolution of figure skating from double jumps to triples to quads, what champion skaters are doing now is almost beyond the ken.
“The sport continues to evolve,’’ Tanger said. “It is really fun to see that kind of evolution. That is what is exciting about an active sport—that evolution. If evolution did not occur, it would just become theater.” five weeks.
Intriguing facts about eyes and vision
• The image projected onto the back of our eyes is upside down and our brain decodes it so that we perceive it the right way up.
• Experiments by MIT scientists show that the human brain can process and correctly identify images seen for as little as 13 milliseconds.
• When it comes to vision, eyesight is only part of the equation — visual information is captured by our eyes but processed by more than 30 areas of the brain.
• The muscles that control your eyes are the most active muscles in your body.
• Concentrated at the outer edges of the retina, rod cells are involved in peripheral vision. They are far more sensitive to light than cone cells, which is why you can sometimes see stars out of the corner of your eye at night, but when you look straight at them they seem to disappear.
• The 'red eye' effect in photos occurs when light from the flash bounces off the back of the eye, where there are many blood vessels.
