I do some sporadic strictly freediving related training,some tables,drystatics training,apnea working, I do breatholds while performing work that usually should be done with a mask,like emtying the dust from my industrial vacumecleaner,cutting tiles/bricks etc. One thing that worries me with the freediving oriented training programs is that they are designed for pushing yourself really hard a couple of times,whereas when spearfishing you dive repeatedly well within your max,but diving stamina is what is recuired..I like to compare freediving and spearfishing to sprinting and marathon, its both running,but the training is diffrent.
When I started freediving/spearfishing a few years ago my static max was just over two minutes,and my average spearing dive was 40-60 seconds,now my static is a bit over four and a half minutes and my spearing average is 1minute-1 minute 20 seconds,I guess I have a higer "safety" factor now than then.
In the pool I used to do hundred meter laps with a one minute static on the bottom of the deep end (5m),it would take me just under two minutes to swim the hundred meters,slow swimming as if holding my position in a current.An hour or so of this a couple of times a week has worked a treat,but now I have to come up with something else,Its abit too cold and icy for running outside for my liking.So maybe a static bike? just for legstrenght and stamina.