Swimming to Success: Maximize Your Potential with Better Fly Kicks

“Swimming is all about racing the clock,” declares Aria Eppinger, Class of 2020. She should know: an avid swimmer for 13 years—the last two spent competing for WT—her life revolves around the sport, from fueling herself with five meals daily plus snacks, to attending seven to 10 practices each week to improve strength, power, and technique. “I do have a tendency to walk into school with wet hair, smelling like a pool,” admits the distance swimmer.
From one of those practices came the beginnings of Swimming to Success: Maximize Your Potential With Better Fly Kicks, an application that shows swimmers how to manipulate their underwater kicks to increase propulsion—and drop time. Swimmers use underwater kicks, interchangeably called fly and dolphin kicks, to propel off starts and turns. Because such kicks create less drag than swimming on the water’s surface, they are key to improving a swimmer’s speed: the more force her kicks generate, the faster she is likely to be. Athletes like Michael Phelps, winner of eight gold medals in the 2008 Beijing Olympics, have proven just how crucial underwater kicks are in a sport where tenths and hundredths of seconds can make all the difference.

Inspired by a friend’s comparison of underwater kicks to sine waves, Aria dove into the concept in Advanced Topics in Mathematics, applying Newtonian physics and simple harmonic motion to model the kicks and develop a formula for calculating maximum force, later realizing she could better analyze the model using multivariable calculus. Although Swimming to Success is built with physics and complex mathematics, swimmers don’t need to understand either to use the app. They only need a smartphone or camera to record their underwater kicks. The resulting video plays on a computer or similar device—at regular speed, in slow motion, or paused—allowing users to gather data such as water measurements; the length and timing of each kick; and the highest and lowest points of their feet while kicking. Next, users impute these parameters to generate a self-calculating spreadsheet detailing kick improvements specific to their needs. Swimmers can even try different kicks to see which propels them the most. 
Aria says her model suggests that “overall, kicking faster rather than larger yields greater increase in propulsion and a better swim.” But, as she wrote in Sigma, WT’s STEM magazine, “swimming technique is largely individual…this is why our application is perfect! It enables all swimmers to see the force generated from their kicks without hydrophysists and thousands of dollars. Swimmers can then play around with their kick and see what uniquely works best for them, easily and cheaply. In just one hour, you can run a few trials, find a better fly kick, and drop tons of time!”
The project taught Aria more than how to improve her fly kicks. She also learned “that scientists aren’t just pipetting in a lab; they can be mathematicians and problem-solvers with equations hunting for variables.” As passionate about STEM as she is about swimming, Aria will spend much of her summer in a lab at the University of Pittsburgh, working on a Hillman Cancer Center Academy research project—when she isn’t in the pool.

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