Complete Guide to Understanding FRC in Freediving: Part 1


Ought to you’ve been inserting around freedivers lengthy ample, you’ve doubtlessly heard the initials ‘FRC’ win talked about. FRC is a term introduced in an intermediate or (on the whole) evolved freediving path – for a merely reason, too.

FRC diving is completely invaluable for freedivers who can already dive with ease to 30m/98toes and want to prepare for even deeper depths.

It’s critical to recollect the fact that until you would also be already freediving simply to 30m or deeper, you fabricate NOT need to comprise FRC dives into your training.

Ought to you’re diving shallower than 30m and want to circulate deeper, your targets are to kick back, revel in, and continue progressing depth safely.

But whenever you already whisk 30m or deeper and want to take cling of more about FRC and what it manner to your freediving, this 3-fragment e-book is right here to quilt some finer theoretical aspects.

Show camouflage that freedivers ought to restful ONLY strive their first FRC dives and training below the guidance of a honorable freediving teacher or coach. FRC dives can end result in well-known injuries if not approached accurately and safely. Self-learned FRC diving by articles or movies is NOT urged.

Now that we got that out of the methodology, let’s start.

What exactly is FRC?

Freediver diving under the guidance of an instructor.
Freediver diving below the guidance of an teacher.

FRC stands for practical residual skill, a measurement of a sure quantity of air in the lungs.

If we spend a deep breath and take care of it, that’s known as our total lung skill (TLC). TLC in a median adult is ready 6 liters, with biological males tending to possess an even bigger TLC than biological females.

FRC is roughly 50% of your TLC – in assorted phrases, it’s the air that remains in your lungs after a passive exhale. A passive exhale is outlined as taking a breath and letting the air float out of your lungs naturally without activating any breathing muscles (if muscle activation occurs, it’s miles a ‘compelled’ exhale).

While you hear freedivers speaking about FRC diving, they indicate that they spend a corpulent breath and then passively exhale sooner than they dive. Americans can even consult with FRC dives as ‘half-lung’ since freedivers on the whole dive with corpulent lungs.

Some freedivers would possibly maybe well also merely additionally mistakenly name them ‘exhale’ dives, but this is indecent as ‘exhale’ dives consult with RV (residual volume) dives, which is a self-discipline strictly for professional, deep freedivers.

Why fabricate some freedivers notify FRC?

Residual volume, or ‘failure depth’

Freedivers must eventually overcome failure depth on their way to deeper depths. Photo by Daan Verhoeven.
Freedivers need to finally overcome failure depth on their methodology to deeper depths. Photograph by Daan Verhoeven.

Let’s focus on ‘failure depth.’

Many freedivers hit a roadblock between 30-40m (98-131toes) because those depths are where we reach residual volume (RV, one other lung measurement).

Residual volume is the air in the lungs after a corpulent (compelled) exhalation.

In untrained adults, RV is on the whole about 25% of their TLC, while freedivers can notify to reduce their RV to about 20% of their TLC. The depth where you reach RV is also known as a ‘failure depth’ because it’s miles where normal equalization (Frenzel) would fail.

So whenever you would also be a median human, you’ll reach RV at 30m (98toes). And whenever you would esteem to notify to circulate deeper? You would possibly maybe well presumably also theoretically many times dive to 30m or more to notify ‘deep.’ On the loads of hand, it would possibly maybe possibly possibly be dreary and make up too mighty nitrogen if ground intervals aren’t respected. But whenever you dive FRC, you would also reach RV at 10m (33toes) as a exchange. But why is that?

Boyle’s Regulations revisited

Build you have in mind Boyle’s Regulations, which states that ‘at a fastened temperature, the volume of a gasoline is inversely proportional to the tension exerted by the gasoline?

Let’s inform you’re a median human with a TLC of 6 liters. Consistent with Boyle’s law, at 10m (33toes), the ambient tension that surrounds you is 2 bar, which reduces your lungs to ½ of their volume (3L). This continues the deeper you dive, where the ambient tension around you will enhance. So in case your RV is 25% of your TLC (1.5L), you would reach failure depth at 30m (98toes), which is 4 bar.

But whenever you dive FRC, which is completely 50% of your TLC (3L), you would reach RV mighty faster. Basically, you would reach it at only 10m (33toes) since your RV is restful at 1.5L.

Take a look at the graphic below for a visual.

FRC diving depth simulation figure from the Molchanovs Lap/Wave 3 course manual.
FRC diving depth simulation figure from the Molchanovs Lap/Wave 3 – Grasp Freediving path handbook.

Drawl depth without going ‘deep’

Diving FRC manner you would also notify to expand your failure depth many times without reaching 30m (98toes) or deeper. This is accessible in to hand for of us that vary into a 40m+ (131toes) freediver and repeated dives to depth change into restricted (or nonexistent – 60m+/197toes divers can only originate one deep dive a day)! It’s also generous when depth is restricted.

No longer only will your physique thank you for avoiding exposing it to too mighty nitrogen make-up (which is in a order to end result in decompression sickness), FRC diving manner you would also many times practice issues esteem deep equalization, training lung flexibility, and sustaining relaxation at depth.

In Section 2 of our Total 3-Section E-book to Working out FRC in Freediving, we’ll ingredient the advantages of FRC dives and why it’s miles useful to comprise them in your training sessions.

Defend tuned!

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