i dont know if its just me, but most of what was said in previous thread was the opposite of what you understood....I guess the anaerobic fast twitch fibers will be more useful towards the end of the dive.
... I think my muscles are mostly aerobic slow twitch and if this really is a disadvantage in freediving, how do I change?..
1st, the fast switch muscles are for maximal and explosive bursts of energy, they get depleted fast
tho you can use them to start a deep dive by doing a good kick to propel yourself down, or a good kick on the walls in a pool dynamic
a good duck dive and subsequent strong kicks will propel you very fast to the neutral buoyancy depth, and you wont need much more kicks to sink
but on ascent you will be using slow aerobic fires or and anaerobic lactic ones
tho lactic producing fibres arnt as efficient as aerobic slow ones, but they are useful to buffer your dynamic dives
you want to reduce O2 usage as much as possible, so using lactic acid as energy buffer is a good strategy
but you may also hit another wall if they make your blood too acid on top of your CO2
and for repeated dives, relying on lactic acid producing fibers isnt a good strategy for endurance, like for spearfishing
but this all depends on how many times you dive and what kind of spearfishing you're doing
collecting molusques and crabs isnt the same as waiting for big games and then wrestling with them, the later relies on anaerobic efforts more