Physics professor marvels at Biles
Soaring high enough to dunk with her toes is one of measurable feats
In her quest for excellence, Simone Biles has any number of things going for her — a compact frame, tremendous core strength, a fierce will to compete and, her mother believes, a physically photographic memory.
“She’s been a perfectionist from day one. When she sees something, that’s how she imitates or adds to whatever she sees. Then she goes and does it,” said Nellie Biles, Biles’ mother and owner with her father, Ron Biles, of World Champions Centre in Spring.
“She might do a little bit of progression, but for the most part, it’s all what she
sees and what she retains. It’s all memory. She would study it and then says, ‘Let me try it.’ I mean, that’s crazy. No one does that. She is able to re-create what she sees in her mind.”
The conjunction of mind and body with the limitations of the physical world are points of fascination for John Eric Goff, a wouldbe baseball pitcher who turned to physics as a profession. He is a professor at the University of Lynchburg, a member of the International Sports Engineering Association, and author of “The Physics of Krav Maga” and “Gold Medal Physics: The Science of Sports.”
Goff studied video of Biles’ recent performances and came away with some remarkable data points on the magnitude of her skills and the precision with which they are accomplished.
• On Biles’ latest signature move, the Yurchenko double pike vault, she reaches a top speed of about 15 mph on the runway, hits the trampoline at its very end to achieve maximum lift, touches the vaulting table with her hands for one-sixth of a second and, at the top of her vault, is upside down with her feet 10 feet above the floor.
Her maximum rotational speed is 150 revolutions per minute, or about one-third the rotational speed of helicopter blades. She completes one revolution in 0.4 seconds, roughly the amount of time it takes a Major League Baseball pitcher’s fastball to reach home plate.
“At the top of her vault, she could dunk a basketball with her toes,” Goff said.
• On balance beam, Goff said, Biles’ legs rotate at a rate of 125 rpms on a forward somersault skill. On three consecutive back somersaults, her margin for error in staying on the beam and not falling off is only 3.7 degrees to either side.
“Her core strength is phenomenal, and that is what is needed to execute her balance beam moves,” he said.
• On floor exercise, Biles reaches a top speed of 11 mph on her first tumbling pass and launches off the mat at a speed of 13 mph, a little less than half the speed that Usain Bolt reached while setting the world record at 100 meters. She is nearly eight feet above the mat at the height of her first somersault.
“She does what she does in the air because of a strength and a flexibility that most of us will never know,” Goff said.
• Uneven bars, Biles’ least favorite event, offers no eye-popping figures but does fascinate Goff for the elements of energy transferal needed to complete a routine.
“Changing heights means changing gravitational potential energy. Such changes are noticed in how kinetic energy changes,” he said. “Stretching arms also represents a form of potential energy, that of the stored energy in stretched tendons and muscles.
“The uneven bars routine represents a fascinating, rapid backand-forth between various types of energy. Once again, gymnasts with strong core muscles and elite fast-twitching muscle groups are capable of these rapid energy transfers.”
In summation, Goff said Biles’ performances are made possible in part by her success in harnessing an element of physics known as angular momentum conservation.
“Angular momentum is the product of rotational velocity with moment of inertia, which measures how mass is distributed about a rotation axis,” he said. “If there are no net, external torques acting on an object, angular momentum is conserved. It’s why a skater pulls her arms and legs in close to her body during her final spin. Lowering her moment of inertia increases her spin rate.”
Biles, Goff said, “is a powder keg of energy and excitement. She has a near-perfect physique for gymnastics. Powerful legs arched back and extremely strong core muscles contribute to a body wellsuited for running, jumping, spinning and twirling.”
Laurent and Cecile Landi, who took over as Biles’ coaches in late 2017, said they inherited a gymnast with sound fundamental skills and technique. That set a baseline, they said, for improvements over the last three years that not even Biles thought would be possible.
“If you have the right fundamentals, you last longer, and you still improve through the years,” Laurent Landi said. “When you rely too much on physical abilities, you hurt yourself quickly and reach your top very soon.
“Even at an older age for a gymnast (24), she is still working on fundamentals every day to try to make the skill even more effortless. When people watch her at her prime, they think it’s easy, It’s not easy. What you see is somebody doing great gymnastics because they have fundamental skills behind them.”
With the addition of the Yurchenko double pike, Laurent Landi said Biles’ four-event program, which could feature as many as to five elements named for her, “is the hardest competitive program she can do right now.”
Goff agrees that Biles “is nearly at the limits set by the constraining laws of physics.”
“By running faster and jumping higher than most gymnasts, she has a decided advantage in artistic expression. She can create more energy with her running, and by jumping high, she can do more in the air than almost anyone competing against her.”
Biles also thinks she has topped out, although she thought the same thing, she admits, in 2016.
“I kind of have achieved it all, and now it’s just like little things,” she said. “Whenever I see people suggest things, I’m like, oh, that would be so fun to do. And I wish I could do that, but I’ve already achieved so much and pushed the boundaries so much.
“I can’t be too selfish, you know.”