Is the "Undulation" Necessary? - Why Large Dolphin Kicks Can Be Counterproductive
Hello everyone, this is Yoshi, the Flipper President!
"Undulate more!"
If you are into swimming or fin swimming, haven't you heard this at least once? From my time as an athlete to becoming a coach, how many times have I heard this phrase and said it myself?
But have you ever stopped to think about it?
"To begin with, what is undulation?"
"How can I undulate well?"
"Is bigger really better when it comes to undulation?"
Today, I will delve into the essence of this "undulation" and talk about the surprising truth behind the "large undulation" that many people misunderstand.
I think this is a great opportunity to reset your swimming form, so please read until the end and use it to improve your own swimming!
The Confusion Surrounding Undulation and Evolving Perceptions
Basic Concepts and Transitions of Undulation
First, let's organize the basics of what "undulation" actually is.
As you know, the "undulation" often used in dolphin kicks and fin swimming is a movement that uses the entire body like a wave to push water backward. It might be easier to imagine the swimming of a dolphin or a tuna.
About 20 years ago, when I started competing, the mainstream coaching advice was "Use your hips more!" or "Undulate bigger!" It was considered good to make your body wave as large as possible.
But interestingly, this perception has been changing year by year.
In fact, even compared to 10 years ago, the coaching content has changed significantly today.
In current top-level environments, the focus has shifted away from just undulating largely, and instead toward how to use the thoracic cage (chest area) and shoulder blades. This is a result of swimming techniques becoming more refined every year.
Misunderstandings and Challenges Seen in the Field
The reality is that the phrase "Undulate!" alone is difficult for beginners to understand in terms of what they should specifically do.
Walking along the poolside, I still often hear the voice saying, "Undulate bigger!" But when I watch the athletes who hear that and actually try to do it...
"Ah, that's not quite right..."
I often feel that way.
This is because, in many cases, "undulating" has become an end in itself. This is putting the cart before the horse. Undulation is not the goal; it is merely a means to an end.
The Science of Undulation - The Boundary Between Efficiency and Inefficiency
The Function of Undulation from the Perspective of Fluid Dynamics
Let's consider the mechanism for moving efficiently through water.
As I always say, water is a fluid about 800 times denser than air. To use an analogy, it's like the difference between walking through an empty train car and walking through a packed rush-hour train car.
How do you move forward efficiently in this dense water? That is the eternal theme of swimming.
Marine creatures like dolphins and tuna have acquired the most efficient methods of propulsion through millions of years of evolution.
That is wave propulsion, or "undulation." By using the entire body like a wave, they firmly grasp the water and push it backward. This movement becomes the driving force for forward motion.
But, what is important here is...
The Paradox of Undulation - The Importance of Quality Over Size
In conclusion, the essence of undulation is that it is merely an auxiliary movement to amplify the power of the kick.
Understanding this is the most important thing.
Imagine this. When you perform a dolphin kick, or when you kick while wearing fins, what matters is firmly grasping the water and pushing it backward. So, what happens if you move your body too much up and down?
Actually, undulation that is too large can be counterproductive.
This is because you use energy to create that large undulation. And above all, if you move too much up and down, the direction in which the propulsion you worked so hard to create acts changes.
The force that was originally meant to move you forward is converted into vertical movement. This is nothing more than a waste of energy.
To use an analogy, it is like a car revving its engine to move forward, but using part of that power to shake the car body up and down. This is clearly inefficient, isn't it?
The Biomechanics of Ideal Undulation
Ideal undulation is one that achieves maximum propulsion with minimal movement.
It involves keeping the core (the central part of the abdomen and back) stable while maintaining appropriate flexibility. And it means smoothly connecting the chain of muscles from the ankles to the knees, hips, and shoulders.
This allows for the efficient transmission of energy with minimal movement.
"Simply reducing excess undulation allows you to swim faster with the same amount of effort"; this is a concept practiced by many top swimmers.
Optimal Undulation Based on Individual Differences and Skill Levels
Considerations Based on Physique and Body Type
In fact, the optimal solution for undulation is different for everyone.
There are differences in how athletes use their bodies depending on whether they are tall or petite. Athletes with long legs can generate significant propulsion even with smaller undulations, while smaller athletes may require a different strategy.
The balance between muscle strength and flexibility is also important. Athletes with excellent flexibility excel at smooth undulations that leverage body coordination, while athletes with more muscle strength may find a swimming style that utilizes more powerful kicks to be more effective.
In other words, it is important to understand your own body's characteristics and find the undulation that suits you.
Differences in Approach Based on Skill Level
If beginners focus too much on undulation, their swimming form can actually fall apart.
In my coaching, I have seen many cases where beginner athletes who were told to "undulate more" actually ended up with slower times.
This is because they focus so much on undulating that their basic form breaks down. Specifically, coordination, kick strength, and directionality are compromised, resulting in a loss of propulsion.
Conversely, it is not uncommon for athletes who do not consciously focus on undulation, but end up undulating as a result, to perform better. It is ideal to first firmly master the basic form and then gradually incorporate elements of undulation.
Even for intermediate and advanced swimmers, it is important to be conscious of swimming for the sake of undulation rather than undulating to swim fast.
Differences Based on Competitive Characteristics
The way undulation is used differs between fin swimming and competitive butterfly swimming.
Fin swimming requires more efficient undulation because it reaches higher speeds. As speed increases, water resistance grows, so unnecessary movements lead to greater energy loss.
In fin swimming, where speeds are 1.5 times faster than competitive swimming, water resistance is more than double. That is precisely why a refined, efficient undulation that does not hinder forward progress becomes even more critical.
Approaching Ideal Undulation - Balancing Contradictions
Resolving the Contradiction of "Minimal Undulation x Maximum Kick"
What I am currently teaching my athletes is the following concept, which may sound contradictory at first glance.
Draw out maximum kick power with minimal undulation!
This is not easy. To strike an effective kick while suppressing undulation, you need a delicate balance in how you use your body.
For example, while keeping upper body movement to a minimum, you must utilize the flexibility of your rib cage (chest area) and effectively use your abdominal and back muscles to firmly transmit that energy to your legs.
Swimmers who master this balance will not appear to have large undulations, and even if it looks like they are swimming only with leg power, they will be able to firmly catch the water with their entire body and generate powerful propulsion.
Practical Training Methods
A step-by-step approach is effective for acquiring ideal undulation.
First, land training to increase core stability and flexibility. Start with basic core training like the planks introduced previously, and gradually incorporate dynamic elements such as exercises using a balance ball.
In the water, start by getting a feel for the kick while keeping undulation to a minimum. Drills performed while holding the wall or swimming practice in the water are effective.
The sensation of strengthening your kick while suppressing undulation might feel strange at first, like "Is it okay that I'm not kicking this much!?" However, calmly facing that discomfort is the shortcut to improvement.
At that time, checking your swimming objectively with video recording can help you realize, "I'm actually moving this much!" making it easier to visualize.
There is often a large gap between the undulation you feel and your actual movement. High-level swimmers have a high ability to perfectly align these two.
Summary: Grasping the Essence of Undulation
Important Insights Regarding Undulation
Let's summarize the important points regarding "undulation" that I shared today👇
Undulation is merely a means to amplify kick power; undulation itself is not the goal.
Excessive undulation causes precious propulsion to escape in the vertical direction.
Ideal undulation varies depending on an individual's physique, flexibility, and muscle strength.
The balance of drawing out maximum kick power with minimal undulation is important.
Ultimately, the goal is to be able to perform optimal undulation without being conscious of it!
This is the ideal state as I see it. Just as a skilled pianist can perform without being conscious of the musical notes, the goal is for your body to naturally find the optimal movement.
Bridging to Practice
For your practice starting tomorrow, the first thing I want you to be conscious of is taking an objective look at your own swimming.
For example, ask yourself if you are forcing your upper body to undulate, or if you are "swimming just for the sake of the undulation?"
Then, try an experiment where you suppress the undulation a little. It might feel strange at first, but new sensations can emerge from that.
In the long term, please gradually acquire the ideal sense of undulation through core training and video feedback.
Perfect swimming is not mastered overnight. However, by understanding the essence of "undulation," your swimming will definitely change!
With that said, thank you for reading this far this time as well.
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See you next time!
See you later!
Finswimming Specialist
Finhin President Yoshihide Sekino
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