The Editor says: Freediving is a sport that demands a deep understanding of your own body. Compared to scuba diving, the descent is far shorter — making every breath all the more precious, and ear equalization the very first challenge every freediver must overcome. Like many beginners, I used to get completely confused between the two equalization methods — Valsalva and Frenzel. A big thank you to Free Corner 自由潛水 for producing this beautifully crafted video that clearly shows the difference between the two!
The following video and text are excerpted from the Free Corner 自由潛水 Facebook page.
The video opens with a vertical descent from the surface, illustrating the water pressure and degree of gas compression a freediver faces at different depths — from the lungs being compressed to half their volume at 10 m, to the freefall that kicks in beyond 30 m, where a diver sinks without any effort. At 30 m, it is also the moment to take a mouthfill; by the time the diver reaches maximum depth, the oral cavity and chest have been compressed nearly flat by the surrounding pressure, underscoring the critical role of the diaphragm in sharing that pressure load and the air consumed from the mouth during ear equalization.
Valsalva vs. Frenzel
The two most common equalization methods in freediving are Valsalva and Frenzel. Although both require pinching the nose to direct air toward the Eustachian tubes, they work in fundamentally different ways. Valsalva relies on the breathing muscles squeezing the lungs to generate positive pressure, while Frenzel uses the muscles at the base of the tongue to push air from inside the oral cavity. The video clearly illustrates both techniques — showing the air source, the muscle groups involved, and the opening and closing of each anatomical structure — along with an animated view of airflow during equalization.
The Story Behind the Equalization Tutorial Video
This video was independently produced by Astrid, with every single frame hand-drawn and animated by her alone — a feat that typically takes an entire team. Yet behind Astrid's professional skills lies a freediving journey that has been anything but easy.
When Astrid first took up freediving last year, she found herself unable to descend smoothly due to ongoing difficulties with ear equalization. She spent a long stretch using Valsalva before finally learning Frenzel, and during that time she would frequently stall at 3 to 5 m, held back by her equalization technique. But she always wore a smile, then calmly breathed up and tried again. I wouldn't presume to say how much she loves the ocean or freediving, but the fact that she made multiple round trips between Miaoli and Kenting just to keep practising speaks for itself. Once, I couldn't help but ask: "Why do you love freediving so much?" Astrid replied, "When you're feeling down, what do you do? I watch freediving videos — one after another — and sometimes I actually get a lump in my throat and feel a rush of warmth in my chest.
I absolutely love how it feels to be underwater, even though I'm not good at it and can't dive very deep." I smiled and said, "Your soul must be a fish. Trust me — with a bit more practice, your body will catch up."
In the course of a few casual conversations, I discovered that Astrid was actually a professional animator. The moment she showed me her first piece of work, I didn't hesitate: "Would you be willing to make a video about ear equalization for FreeCorner? It won't be cheap, but we've never had teaching material that lets students easily understand the different equalization methods — this could be something we create together." "No problem, but it'll take a while since there's a huge amount of work involved," Astrid replied with a cheerfulness that caught me off guard. And that was already last year.
Even a short animation requires countless rounds of communication and alignment to get right — it's genuinely difficult and time-consuming. As Astrid went abroad for school this year, and as I held firm to the belief that a good piece of work should never be rushed, progress seemed indefinitely distant. Then, a few days ago: "Agu, I poured every bit of my longing for the ocean into this video. Take a look and tell me what still needs fixing." With that, Astrid excitedly told me she had used a great deal of her spare time abroad to complete all the items on the to-do list.
Looking at this animation, you may see a tutorial on ear equalization — but for FreeCorner, it represents something far deeper: a vivid reminder that loving freediving can take many forms, and that going deeper is far from the only one. Thank you, mermaid Astrid — beyond freediving, you taught me a lesson I'll carry with me.
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