HTH,
- Get Professional Instruction - PFI seems to be the only game in the U.S. - But with Martin leaving PFI, he may be looking to teach - this coming from a reliable source in France who knows him.
- Realize that freediving is a participatory endeavor - no weekend warriors or posers - train 5 days a week is what I do - Read Umberto Pellizzari's "The Manual OF Freediving" - in my opinion it's the bible on freediving.
- Develop a base level of cardio fitness, but then take it up a notch and begin doing cardio while in short states of Apnea - I use an arc trainer 3 days a week at the gym and do almost 60 minutes of variations in apnea cardio training - this will develop a higher level of efficiency of the body when levels of CO2 are present. Find the Static Apnea tables (google them) - they are key to developing your breath hold.
- Pool training is important. Technique is crucial - anyone who bicycle kicks with long blades needs to go get some help. And the vast majority of spearo's have some of the worst technique I have ever seen. It took Aahron Solomons to drum that into my head when I trained with him last year.
- DON'T buy plastic blades - they only FUBAR any amount of technique you might develop. Get real long blades (preferably glass composite at a minimum), make sure they aren't stiff - believe it or not, one can be more efficient with a softer blade underwater - Get a good low volume mask - no scuba masks!!!