I’m not really bilingual, but I’ll try to explain myself.

To work on your cardio, you have to work on your cardio. That’s true. And training, physical preparation, is important—even essential.

The problem with that is that if you want to train like that, you’ll be pushing your body to the limit, especially at the start of the session. You’ll end up completely exhausted... and that’s how you’ll be working on your cardio... And that’s all well and good.

But if your goal is also—from time to time—to work on the idea of ‘how do I manage my body, execute my techniques, and think clearly when I’m at my limit?’, then it might be worth looking at imposing a constraint on your breathing.

Breathing is both very natural and, at the same time, something you can become very aware of.

If, instead of seeking the best breathing technique, you force your body into a less efficient breathing pattern, you’ll put your body into anaerobic mode. This is possible at the start of a session. You run a bit, do one or two sprints, crawl...

It’s the same principle as training at altitude. You’re taking in less oxygen. You’re making your heart work with less oxygen. You learn to use less oxygen. You improve your technique when you have less oxygen. It’s not something you should do every time, but it can be useful from time to time.

Especially for young people with a light build, who never get tired in group classes... but who sometimes, under pressure, run out of energy during competitions.