tightly streamlined ones traveled a looooong way before they began stroking. They really looked like fish in an aquarium — so long as they were in streamline. The moment they began pulling and kicking, they worked much harder and moved much slower.
Those who maintained a sleek shape could cover up to eight fast and easy yards before they took their first stroke. Any swimmer not tightly molded into a torpedo shape lost speed so dramatically that they looked exactly as if they'd run into a wall. And they had. To a poorly streamlined body, the water is a wall. I understood, in that instant, that the primary thing limiting how fast my swimmers could go was not the workouts I spent hours devising, but the effect of drag on their bodies. Clearly the most valuable skill to teach was streamlining — not just on the pushoff, butthe whole length of the pool.
This was a logical conclusion, based on the fact that water is over 800 times denser than the "thin" air that costs cyclists such a stunning amount of energy. In a medium as thick as water, the payoff for reducing drag at even the slowest speeds can be enormous. And water gets "thicker" as you go faster: Drag increases exponentially as speed goes up, so the payoff for avoiding drag also increases exponentially the better you avoid it.
Why Water Is a Wall
Boats, cars, and planes avoid drag best when they are long, sleek, and tapered. Humans can enjoy a moment or two of that as we push off, but as soon as we begin stroking again, most of us revert to blocky and angular shapes. (Seeing these shapes for the first time on slow-motion underwater video is an incredibly revealing moment for students at TI workshops.) Fast swimmers maintain the most streamlined position as they stroke; slow swimmers do not. This is the most important distinction between them.
But drag isn't just some general retarding force. There are three distinct forms of drag, which you can avoid better by understanding them. Two can be minimized by changes in technique, one by changing your suit.
1. Form drag is resistance caused by your human-body shape. As you swim, you push water in front of you, creating an area of higher pressure. Behind you, your body leaves a turbulent swirl, creating an area of lower pressure. Higher pressure in front and lower pressure behind creates a vacuum that, in effect, sucks you back. (That's why drafting off other swimmers — or cyclists — feels so much easier. The low-pressure area trailing the swimmer in front of you sucks you forward.) Form drag increases as the square of your velocity. Thus, twice as fast means four times as much form drag.
Your body's size and shape determine form drag, and the best way to minimize that drag is to pierce the water or slip through the smallest possible "hole." You do that by staying in a balanced, horizontal position and by making sure any side-to-side movement is rotation — not snaking or fishtailing. TI Coach Emmett Hines puts it succinctly: "If you're perfectly streamlined — as in the pushoff — any motion will increase form drag." That means it's critical, once you begin swimming after the pushoff, to make your propelling actions as smooth and economical as possible. Concentrate, even as you pull and kick, on fitting through the smallest possible hole in the water, and you'll be on the right track.
And, while swimming freestyle, you're at your sleekest when you spend most of each stroke cycle on your side, particularlyin the brief interval between strokes. But doing that requires an impeccable sense of dynamic balance and side balance.
2. Wave drag. Just like a boat, you leave a wake while swimming. Wave drag is the resistance caused by the waves or turbulence you create. As Hinesquips, "Making waves takes energy — all of it supplied by you. "The bigger your wake, the greater your energy loss. Unlike form drag, which increases as the square of velocity, wave drag increases as its cube. So as you double your speed, energy
Those who maintained a sleek shape could cover up to eight fast and easy yards before they took their first stroke. Any swimmer not tightly molded into a torpedo shape lost speed so dramatically that they looked exactly as if they'd run into a wall. And they had. To a poorly streamlined body, the water is a wall. I understood, in that instant, that the primary thing limiting how fast my swimmers could go was not the workouts I spent hours devising, but the effect of drag on their bodies. Clearly the most valuable skill to teach was streamlining — not just on the pushoff, butthe whole length of the pool.
This was a logical conclusion, based on the fact that water is over 800 times denser than the "thin" air that costs cyclists such a stunning amount of energy. In a medium as thick as water, the payoff for reducing drag at even the slowest speeds can be enormous. And water gets "thicker" as you go faster: Drag increases exponentially as speed goes up, so the payoff for avoiding drag also increases exponentially the better you avoid it.
Why Water Is a Wall
Boats, cars, and planes avoid drag best when they are long, sleek, and tapered. Humans can enjoy a moment or two of that as we push off, but as soon as we begin stroking again, most of us revert to blocky and angular shapes. (Seeing these shapes for the first time on slow-motion underwater video is an incredibly revealing moment for students at TI workshops.) Fast swimmers maintain the most streamlined position as they stroke; slow swimmers do not. This is the most important distinction between them.
But drag isn't just some general retarding force. There are three distinct forms of drag, which you can avoid better by understanding them. Two can be minimized by changes in technique, one by changing your suit.
1. Form drag is resistance caused by your human-body shape. As you swim, you push water in front of you, creating an area of higher pressure. Behind you, your body leaves a turbulent swirl, creating an area of lower pressure. Higher pressure in front and lower pressure behind creates a vacuum that, in effect, sucks you back. (That's why drafting off other swimmers — or cyclists — feels so much easier. The low-pressure area trailing the swimmer in front of you sucks you forward.) Form drag increases as the square of your velocity. Thus, twice as fast means four times as much form drag.
Your body's size and shape determine form drag, and the best way to minimize that drag is to pierce the water or slip through the smallest possible "hole." You do that by staying in a balanced, horizontal position and by making sure any side-to-side movement is rotation — not snaking or fishtailing. TI Coach Emmett Hines puts it succinctly: "If you're perfectly streamlined — as in the pushoff — any motion will increase form drag." That means it's critical, once you begin swimming after the pushoff, to make your propelling actions as smooth and economical as possible. Concentrate, even as you pull and kick, on fitting through the smallest possible hole in the water, and you'll be on the right track.
And, while swimming freestyle, you're at your sleekest when you spend most of each stroke cycle on your side, particularlyin the brief interval between strokes. But doing that requires an impeccable sense of dynamic balance and side balance.
2. Wave drag. Just like a boat, you leave a wake while swimming. Wave drag is the resistance caused by the waves or turbulence you create. As Hinesquips, "Making waves takes energy — all of it supplied by you. "The bigger your wake, the greater your energy loss. Unlike form drag, which increases as the square of velocity, wave drag increases as its cube. So as you double your speed, energy
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