Science MADE EASY
The Laws of Water
Understanding the Physics Behind Swimming Speed
1
The Equation of Speed
At the foundation of swimming speed lies a simple equation, where:
Metabolic Power - total energy produced by the body.
Mechanical Efficiency - how effectively that energy is converted into movement.
Propulsive Efficiency - how effectively you interact with the water to create propulsion.
Total Resistance - sum of Active and Passive drag forced opposing motion.
Metabolic Power - total energy produced by the body.
Mechanical Efficiency - how effectively that energy is converted into movement.
Propulsive Efficiency - how effectively you interact with the water to create propulsion.
Total Resistance - sum of Active and Passive drag forced opposing motion.
«Swimming speed can be described through these main components.
At its core, your metabolic power represents the total energy your body can produce — the engine that drives every movement.
However, raw energy alone doesn’t define speed. What truly matters is how efficiently this energy is transformed and transferred into motion.
The first level of this transformation is mechanical efficiency — the ratio between your total external mechanical power output and your metabolic energy.
It reflects how effectively your muscles convert biochemical energy into physical work in the water.
Every wasted motion, every unstable position, reduces this efficiency.
The second level is propulsive efficiency — how effectively you interact with the water itself.
It describes how much of your mechanical work is transformed into useful propulsion, rather than turbulence and drag.
It’s not only about strength — it’s about timing, feel, and connection with the flow.
Finally, all of this is balanced by resistance — the sum of active and passive drag forces acting against you.
Active drag comes from your movements; passive drag, from your body position and form.
The faster you go, the stronger these forces push back.
- To swim faster, you don’t simply add more power — you optimize the harmony between energy, efficiency, and resistance.»
At its core, your metabolic power represents the total energy your body can produce — the engine that drives every movement.
However, raw energy alone doesn’t define speed. What truly matters is how efficiently this energy is transformed and transferred into motion.
The first level of this transformation is mechanical efficiency — the ratio between your total external mechanical power output and your metabolic energy.
It reflects how effectively your muscles convert biochemical energy into physical work in the water.
Every wasted motion, every unstable position, reduces this efficiency.
The second level is propulsive efficiency — how effectively you interact with the water itself.
It describes how much of your mechanical work is transformed into useful propulsion, rather than turbulence and drag.
It’s not only about strength — it’s about timing, feel, and connection with the flow.
Finally, all of this is balanced by resistance — the sum of active and passive drag forces acting against you.
Active drag comes from your movements; passive drag, from your body position and form.
The faster you go, the stronger these forces push back.
- To swim faster, you don’t simply add more power — you optimize the harmony between energy, efficiency, and resistance.»
Max
Thoughts
2
The Balance Between Power and Efficiency
Speed doesn’t grow by simply adding force.
It grows when power increases while resistance decreases, and when the swimmer learns to apply just the right amount of force to the moving flow of water. When your effort matches the hydrodynamic flow, propulsion efficiency rises. When your effort exceeds the optimal level, excess power turns into turbulent energy — wasted motion, splashes, and drag.
In swimming, mechanical efficiency — the strength of your stroke — is often at odds with propulsive efficiency — your feel of the water. If you chase raw strength without control, you lose connection with the flow. Too much power is as dangerous as too little. Speed in water is born not from aggression, but from intelligent interaction — optimal power, perfect flow, minimal resistance.
It grows when power increases while resistance decreases, and when the swimmer learns to apply just the right amount of force to the moving flow of water. When your effort matches the hydrodynamic flow, propulsion efficiency rises. When your effort exceeds the optimal level, excess power turns into turbulent energy — wasted motion, splashes, and drag.
In swimming, mechanical efficiency — the strength of your stroke — is often at odds with propulsive efficiency — your feel of the water. If you chase raw strength without control, you lose connection with the flow. Too much power is as dangerous as too little. Speed in water is born not from aggression, but from intelligent interaction — optimal power, perfect flow, minimal resistance.
« The art of balance lies in control.
Stroke length and stroke rate define how efficiently power turns into speed.
When they’re in harmony, every movement pushes you forward with purpose — not through force, but through precision.
The swimmer who learns to control both doesn’t chase the water — he moves with it. »
Stroke length and stroke rate define how efficiently power turns into speed.
When they’re in harmony, every movement pushes you forward with purpose — not through force, but through precision.
The swimmer who learns to control both doesn’t chase the water — he moves with it. »
Max
Thoughts
3
The Physics of Resistance
Resistance in water grows quadratically with speed. When your velocity doubles, drag increases fourfold.
That’s why even a small improvement in body position matters: Raising your body by just 1 cm can reduce drag by up to 4 kilograms.
We divide resistance into two main types:
Passive Drag — created by body position and shape in the water (streamline, alignment).
Active Drag — created by movements that disturb the flow (poor timing, turbulence, instability).
At race speed, pressure drag becomes the dominant force — caused by the pressure difference between the front and back of the swimmer. Friction drag arises from microscopic contact between your skin, suit, and the surrounding water, while wave dragappears when part of the body breaks the surface. Studies show that at around 2 m/s (race pace):
At higher speeds, the penalty grows exponentially — three times more drag at 2 m/s than at 1 m/s.
That’s why elite swimmers look so still in motion — every movement is intentional, nothing is wasted.
A smart swimmer learns to coexist with water, not fight it.
Efficiency isn’t about pushing harder — it’s about removing everything that slows you down.
“The faster you go, the more the water reveals your mistakes.”
Resistance in water grows quadratically with speed. When your velocity doubles, drag increases fourfold.
That’s why even a small improvement in body position matters: Raising your body by just 1 cm can reduce drag by up to 4 kilograms.
We divide resistance into two main types:
Passive Drag — created by body position and shape in the water (streamline, alignment).
Active Drag — created by movements that disturb the flow (poor timing, turbulence, instability).
At race speed, pressure drag becomes the dominant force — caused by the pressure difference between the front and back of the swimmer. Friction drag arises from microscopic contact between your skin, suit, and the surrounding water, while wave dragappears when part of the body breaks the surface. Studies show that at around 2 m/s (race pace):
- Pressure drag accounts for roughly 50% of total resistance.
- Friction and wave drag each contribute about 25%.
- Small shape or position changes — even hand angle, shoulder roll, or head lift — can significantly alter drag.
At higher speeds, the penalty grows exponentially — three times more drag at 2 m/s than at 1 m/s.
That’s why elite swimmers look so still in motion — every movement is intentional, nothing is wasted.
A smart swimmer learns to coexist with water, not fight it.
Efficiency isn’t about pushing harder — it’s about removing everything that slows you down.
“The faster you go, the more the water reveals your mistakes.”
