Glossary

2007 World Championships: William ascends from 75m CNF - © Timo Jattu

Freediving Terms and Definitions
 
Breath-hold diving / Freediving::
 
The act of retaining only air in one’s lungs while diving under the water surface. No breathing apparatus is used, as opposed to scuba diving or technical diving.
 
 
Competitive Indoor disciplines:
 
Dynamic apnea (DYN): This is a distance discipline whereby the freediver dives under the water surface only aided his/her arms and by a monofin or bi-fins. Pool size minimum: 25 min; maximum: none.
 
Dynamic without fins apnea (DNF): This is a distance discipline whereby the freediver dives under the water surface without any propulsive aid. Pool size minimum: 25 min; maximum: none.
 
Static apnea (STA): This is a time discipline whereby the freediver holds his/her breath for as long as possible with his/her airways submerged.
 
 
Competitive open-water disciplines:
 
Free Immersion apnea (FIM): This is a depth discipline whereby the freediver descends and ascends along a line only by pulling on the rope. It can be done head down or feet down.
 
Constant Weight apnea (CWT): This is a depth discipline whereby the freediver descends and ascends along a line only aided by a monofin or bi-fins and by his/her arms but without pulling on the rope.
 
Constant Weight without Fins apnea (CNF): This is a depth discipline whereby the freediver descends and ascends along a line breaststroke style, without pulling on the rope. This is the purest and hardest depth discipline.
 
 
Non-competitive open-water disciplines:
 
No-Limit (NLT): This is the absolute depth discipline. During the descent, the freediver is pulled down by a weight. To ascend, the freediver can choose a method of his/her choice. The usual set up is going down with a weighted sled and ascending with a balloon. Current sled diving practice is done head up.
 
Variable-Weight (VWT): Like No-Limit, the freediver is pulled down by a weight, but unlike No-Limits, s/he has to ascend by pulling on the line. The use of external means of propulsion other than fins is not allowed. Current sled diving practice is done head up.