STREAMLINE EXPLAINED (HOW DO DRAG FORCES INFLUENCE MY BODY IN SWIMMING?)

"Streamline, streamline, streamline", if I had a dollar for each time I say this word, I'd be a multi-billionaire at this stage, live in a mansion and have my own private 50-meter pool with a retractable roof.

If you visit this swimming blog often, you've seen it over and over again. But what does it actually mean, and why do coaches obsess about it so much?

Let's dive in.

Quick Jump To:

• What Is Streamline in Swimming?
• Understanding Drag Forces in Water
• Types of Drag in Swimming
• How to Reduce Drag and Improve Streamline
  • 1. Push Off the Wall at Lower Depths
  • 2. Hold a Perfect Streamline Position
  • 3. Maintain Proper Head Position
  • 4. Use Body Rotation Effectively
  • 5. Wear a Swim Cap
  • 6. Remove Excess Body Hair
  • 7. Choose the Right Swimsuit
• Conclusion: Streamline Equals Speed
• FAQ

What Is Streamline in Swimming?

In simple terms, streamlining means shaping your body to move through the water with as little resistance as possible.

Think of your body as a broomstick versus a small tree. A broomstick slices cleanly through the water; a small tree, with all its branches, creates chaos and turbulence.

That's the difference between a streamlined swimmer and a floppy one. When you swim, the goal is to be the broomstick, straight, tight, and sleek.

Even if you're not a competitive swimmer, good streamline makes every lap easier, faster, and more enjoyable.

The better you are positioned in the water, the more enjoyment you will have from swimming and the more you can swim and learn.

Understanding Drag Forces in Water

Once you've learned to float and overcome gravity, the next challenge is drag, the invisible resistance that slows you down every time you move through water.

The better you understand drag, the better you can control it.

Swimming scientists identify three main types of drag that affect your body, form drag, frictional drag, and wave drag. Together, they determine how efficiently you move.

Types of Drag in Swimming

Let's break them down quickly:

• Form drag:
  Caused by your body's shape and how much turbulence it creates. Humans aren't shaped like fish, so we naturally create resistance.

• Frictional drag:
  Created by water flowing over your skin, suit, and hair. The smoother your surface, the less friction.

• Wave drag:
  The big one. As described in the Journal of Biomechanics' paper "Wave Drag on Human Swimmers," wave drag is the energy lost to waves you create at the surface. The faster you swim, the more wave drag builds up.

Wave drag plays the biggest role in slowing you down, and luckily, it's also the one you can most directly influence through better streamline technique.

There are of course other forces that act on our body when we swim, but these are secondary in the streamline discussion.

Ok, now we know what slows us down in the water.

So, how can we decrease these drag forces to become faster and more efficient in our swimming?

How to Reduce Drag and Improve Streamline

Since the wave drag seems to play the biggest role in slowing our swimming down, let's focus on it first.

As described in the many scientific publications, wave drag increases as our swimming speed increases. In other words, as you swim faster, you are also causing more waves to be formed behind and around you.

And as we said above, the more waves you generate around you, the more wave drag.

Here's how to reduce drag and become a smoother, faster swimmer.

1. Push Off the Wall at Lower Depths

Avoid pushing off right at the surface. Research shows that wave drag drops sharply even 0.5–1 meter below the surface.

That's why the underwater dolphin kick, sometimes called the "fifth stroke", is the fastest movement in swimming. It's also why FINA limits underwater swimming to 15 meters per start or turn.

2. Hold a Perfect Streamline Position

When your coach says "hold your streamline," here's what they mean:

• Arms fully extended above your head
• One hand over the other, palms flat, thumbs locked
• Biceps squeezing tightly behind your ears
• Head tucked, chin down
• Shoulders stretched forward, no air pockets around your neck

This position reduces both form drag and frictional drag by keeping your body aligned like a torpedo.

3. Maintain Proper Head Position

Your head should always follow your spine, not fight it.

• In freestyle, look straight down.
• In backstroke, look straight up.
• In butterfly, your head stays low, only skim the surface to breathe.
• In breaststroke, the head moves as an extension of the spine, not independently, unless you want to exaggerate the head slam back into the water for extra power.

Keeping your head aligned reduces turbulence and prevents drag-producing "bumps" in your body line.

4. Use Body Rotation Effectively

In freestyle and backstroke, rotating your body side-to-side helps extend each stroke and align your body more effectively.

This rotation not only reduces form drag, but also engages your core muscles, giving you more power per stroke with less energy waste.

If you want to go even further and really maximize the drag removal. Here are a few more ways to do that.

5. Wear a Swim Cap

Wearing a swimming cap smooths your head surface, reducing friction drag.

Paired with low-profile goggles, it helps your head cut through the water more cleanly, and keeps your hair from acting like a small parachute.

6. Remove Excess Body Hair

Yes, there's a reason competitive swimmers shave before big meets.
Less hair means smoother skin, less friction, and better hydrodynamics.

Shaving also gives a mental boost, that slippery "fresh skin" feel that makes you believe you're gliding faster (and often, you really are).

7. Choose the Right Swimsuit

Not all swimsuits are created equal.
Some high-tech suits reduce drag by compressing your body and minimizing water resistance.

It worked too well, FINA banned full-body suits after they helped shatter dozens of world records in a single season.

For everyday swimmers, a snug, sleek-fitting suit can still make a noticeable difference.

Conclusion: Streamline Equals Speed

So there you have it, the science of swimming faster without swimming harder.

Reduce drag, perfect your streamline, and you'll glide farther with every stroke.

Whether you're chasing a personal best or just want to make swimming feel effortless, remember: the most efficient swimmer isn't the strongest, it's the one who creates the least resistance.

Now go make your inner broomstick proud and learn more about how your specific swimming style can be improved to reduce drag?