All eyes are on Paris and the 2024 Olympics, and while most people are talking about the Games at hand, scientists are looking toward future games—where we may see a different kind of sprint emerge.
The Basilisk lizard, also known as the “Jesus lizard,” is impressively able to run across the water. It can begin running on land and transition to water to avoid predators, which is amazing given that it weighs around four ounces and is too heavy to be supported by water’s surface tension.
Two Harvard researchers, Tom McMahon and Jim Glasheen, began studying the phenomenon in the 1990s. They developed a mathematical model by analyzing videos of lizards walking on water and found that each step can be broken down into three stages: slap, stroke, and recovery.
As the basilisk runs across the water’s surface, its feet slap the water like a human sprinter’s hitting a track. Each time its foot hits the water, the liquid exerts an upward force. The larger the lizard’s foot and the faster it hits the water, the greater the upward force generated by the slap. During the stroke phase, the lizard moves its foot rapidly, which creates an air bubble above its foot, lifting the foot up. And the final phase, recovery, occurs while the lizard is pulling its foot up and preparing for the next movement.
So, could humans achieve the same result?
In their research, Glasheen and McMahon calculated that a 175-pound human with an average foot size and a world-class sprinter’s stride rate would need to cover the water at a speed of nearly 98 feet per second to support their weight. However, the power required for a stroke at that speed is almost 15 times greater than a human’s maximum sustained output. In other words, no human can run on water on Earth.
But what if there were different physical conditions?
In 2012, a study was conducted at the University of Milan to see whether reduced gravity would enable humans to run on water. Volunteers wore a specialized harness that reduced their weight to a fraction of normal Earth weight. They also wore large fins on their feet, similar to those of a basilisk lizard. In this setup, the volunteers attempted to run in place within a small, inflatable pool.
In video footage of the test, the subjects pumped their thighs up and down, creating choppy water. Their legs stroke into the water about halfway to their knees, but they seem to manage to support their reduced weight for the seven to eight seconds the researchers deemed a success.
The team discovered that all volunteers could run on the water at 10 percent of Earth’s gravity, but as they increased the gravitational force, not all the runners could keep up.
Translation: Water running could be considered an Olympic sport if we held a future edition of the Olympics on a planet or moon with the proper gravitational force.
Physics World says that the lakes on Titan, Saturn’s largest moon, are comparable to Earth’s, while the gravitational acceleration is only 13.8 percent of our home planet. The magazine explains that women’s 100-meter world champion Sha’Carri Richardson could theoretically do it. Richardson would have to slap the water’s surface at about 28 feet per second, generating over 60 percent of the necessary vertical force to propel her. Her world championship time was significantly faster, at around 30 feet per second.
So, while we may not be running like lizards in any near-future Olympic Games, at least we have someone who can do it somewhere in our solar system.
Laura Ratliff is a New York City-based writer, editor, and runner. Laura’s writing expertise spans numerous topics, ranging from travel and food and drink to reported pieces covering political and human rights issues. She has previously worked at Architectural Digest, Bloomberg News, and Condé Nast Traveler and was most recently the senior editorial director at TripSavvy. Like many of us, Laura was bitten by the running bug later in life, after years of claiming to “hate running.” Her favorite marathon is Big Sur.
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