A short introduction to Freediving depth disciplines

If you have been looking into freediving and come across terms such as 'FIM', 'CWT' or 'CNF', and been a bit confused by what they all mean, you have come to the right place!

Most of these acronyms refer to the different freediving 'disciplines', which is the way in which a freediver moves down into the depths and back up. Each discipline has its own rules to consider when in competitions!

FIM
Free Immersion = Pulling oneself down and up on the rope.

In this discipline the freediver uses the rope for both the descent and ascent, while wearing the same weight throughout the entire dive. Often the freediver is not wearing any fins at all when doing FIM, as he or she uses only their arms' strength to pull themselves up and down the line. The advantage here is that you only need to use the smaller muscle groups, those in the upper body (arms and back), which means you are not consuming too much oxygen. FIM dives usually take longer , but it’s also the most relaxing discipline of them all!

CWT

Constant Weight (with bifins)

In constant weight with bifins you have a fin on each foot and use a scissor kick to get you down and up, with the same weight throughout the dive. When competing in the CWT disciplines, athletes are not allowed to hold on to the rope, except once, when turning around at the bottom to go back up.

This discipline requires one to use their large leg muscles to get down and up, but with the right technique and good streamlining, you will be able to reduce your oxygen consumption to a minimum.

This discipline is a real old school discipline which has been existing since the birth of competitive freediving, and seems to be on the rise again!

CWT

Constant weight (with monofin)

The same as above, but with a monofin, meaning both feet are in one large fin, and you swim like a dolphin! Here, one needs to put a bit more emphasis on technique, but when you get it right, you will go deep! CWT with monofin is the self-propulsion discipline with which competitors go deepest, and is likely the one that will get you the deepest too! The reason for this is the relative speed and the energy-efficiency you get from a monofin-thrust.