Quad Toe Loop analysis
Rion Sumiyoshi from Japan is one of the rare Japanese women to attempt jumping a quad-toe loop ( noted 4T ). This young skater, a senior skater this season, tried this jump many times but failed to succeed. We are going to look at the one she did during the last junior World Championships( march 2022), during the ISU Grand Prix of France (November 2022), and the 2023 Japanese National Championships ( December 2022).
Rion has a huge flight time ( around 0.700s / average data is 0.662s). But she needed to catch up in the rotation, so she struggled to land this jump properly. The angular velocity of her snap is between 23.436rad/s ( Slowest) and 25.47rad/s (Fastest); the average is around 25.725 rad/s. After getting primary data, we also noticed her body angle in the air is entirely tilted ( she stays around 17◦).
It’s time to push further investigations.
Why is she slow?
Let’s check her preparation. It’s the part where she generates angular momentum. The turn duration (1.566s / 1.126s / 1.017s) is longer than the average data (0.900s). It will influence the duration of the draw. And guess what? Her best jump ( she got a deduction but still scored 7.19 points ) had a draw time of around 0.150s (The average draw time is around 0.132s).
Data for Rion Sumiyoshi from Japan
In the March 2022 Junior World Championships, Rion landed with a quarter missing (q), then stepped out. She scored 4.75 points
Flight time: 0.700s / Angular velocity of the snap: 25.47rad/s
Duration from the end of the turn ( backward) until the toe pick: 1.566s / Draw: 0.100s
In November 2022, she fell at the Grand Prix de France because of a poor landing. She landed into the “Angle of Fall.” Scored 4.75 points
Flight time: 0.709s / Angular velocity of the snap: 24.634rad/s
Duration from the end of the turn ( backward) until the toe pick: 1.126s / Draw: 0.083s
What is the “angle of fall”?
Due to a body weight transfer at the take-off not being efficient enough or a poor angular velocity, the landing quality is impacted. That’s why the skater could land in the “angle of fall.”
This angle is between under-rotated landing and around 30° (note that 0° is “q”). Landing at this slight angle only allows the skater to fall because of physics and gravity laws. ( This is an extract from the ebook Figure Skating: Jumps Techniques: The Guide to Understanding the Mechanics of the Figure Skating Jumps. Click HERE to order a copy)
In December 2022, 2023 Japanese Nationals q with a poor landing
Flight time: 0.700s / Angular velocity of the snap: 23.436rad/s
Duration from the end of the turn ( backward) until the toe pick: 1.017s / Draw: 0.150s
What should Rion do to improve her success rate?
Option 1
Improve the speed of her snap. In the orange circle, we can see the legs moving after the take-off, then the duration to get the final air position ( noted 1.).
Option 2.
After the foot change, she could get a compelling draw ( noted 2.). The main goal is to face the future landing spot.