What makes Penny go: The science behind Oleksiak’s swimming success

The first thing you notice about Penny Oleksiak is her towering height.

It was what national coach Ben Titley saw immediately when he spotted her at the Toronto Swim Club a few years ago while scouting young swimmers. The next thing he glimpsed was her hands: "They're bigger than mine," he says.

Both are ideal traits for a competitive swimmer – effective for acceleration and glide.

Oleksiak, who's racked up more medals at a single Summer Games than any previous Canadian Olympian, stands nearly 6-foot-2. At 16, she is not only the tallest on the women's team, she'll probably add a few more inches before she's done growing.

In recent days, as the rookie Olympian ensured her place as one of Canada's best-ever swimmers, two questions began to circulate around the swimming world. Just who is Penny Oleksiak? And what makes her so spectacularly good?

The first question is easier to answer: Oleksiak insists she's just a normal high school student from Toronto whose favourite things include social media and dogs. She comes from an athletic family, with parents who both played college sports, an older brother, Jamie, who is a defenceman with the Dallas Stars, and an older sister, Hayley, who is an NCAA rower.

But the second question about what makes Oleksiak so freakishly effective in the water is a more complex algorithm to untangle.

When she won her fourth medal in Rio – a gold in the 100-metre freestyle Thursday night – she looked headed for a miserable loss after the first 50 metres. Stuck in seventh place at the turn, she proceeded to blow past most of the field in the final 25 metres, tying for first with American Simone Manuel and setting an Olympic record.

It was a performance that was as stunning as it was hard to compute.

Three swimming experts – Elaine Tanner, winner of three medals at the 1968 Mexico City Olympics; Swimming Canada high-performance director John Atkinson; and Titley, Oleksiak's coach – spoke with The Globe and Mail to explain the science behind what makes Oleksiak so good.

It starts with her height

When Tanner won Canada's first Olympic medal in women's swimming in 1968, the sport was a lot different. Tanner, whose nickname was Mighty Mouse, claimed two silvers and a bronze medal despite standing just 5-foot-3. "I never really looked like a swimmer," she said.

Most of today's best swimmers are a lot taller, and Oleksiak is at the forefront of that revolution. Tanner says Oleksiak has a body "like a dolphin." It is long, lean and "physiologically built for the water." The height helps generate speed and torpedo-like glide. It also helps Oleksiak reach for the wall before other swimmers, and spring off of it with more power during a turn. Though Tanner was fast, as a shorter swimmer, turns were a challenge for that reason.

It's all about the hands (and maybe the feet)

Much is made about how U.S. legend Michael Phelps has the ideal body for the pool: a massive wingspan, huge flipper-like feet and oversized hands capable of pulling himself through the water. Despite Oleksiak's runaway success in the pool, "she actually doesn't have the perfect swimmer's body," her coach Titley said. "She doesn't have feet as big as what you would expect. Her feet are actually on the small side for her height. But she's extremely long, has an extremely long stroke and big hands."

Bigger hands and longer arms generate more force in the water.

The more the swimmer can recoil their arm on strokes, and the more water they can catch with their hands, the faster they will go, Atkinson says. "With the high elbows, you go into the water and you have more force that you can apply to the stroke," he said. "The stronger you are, the more you can keep the stroke mechanics going through the race."

Every swimmer needs an engine

In each of her races in Rio, Oleksiak has finished the last 50 metres faster than most of the field. Though she starts slower, she is at her quickest in the final 15 metres. This comes down to the swimmer's engine – the heart, the lungs and the fitness to ensure they can kick until the end.

"Having long legs is great, having big feet is great. However, what you have to be is fit in order to maintain a leg kick," Atkinson said. "If people look at that last 15 metres [of Oleksiak's gold-medal race in the 100-metre freestyle], they see the outboard motor that is propelling her, and her ability to really kick."

But where exactly does the engine come from?

Much of what propels a swimmer is mental

Titley looks at Oleksiak and sees a fighter. "She obviously has a great engine where she can close races extremely well," he said.

At 16, Oleksiak is not nearly as strong as she will be in her prime, which may come during the 2020 Tokyo Olympics and beyond.

"She doesn't yet have the strength and power to go out in the first half of races with the girls who are in their early to mid 20s. But that will come in time," Titley said.

What Oleksiak does have in spades, though, is mental toughness – the sense that if she sees a swimmer ahead of her, she is fiercely determined to catch them. Titley figures she developed that coming up in swim clubs where she would dominate her own age group and have to battle when put in races against older kids.

"Part of it is mental," he said. "Part of it is her upbringing."