For those interested, I would add that doing all your training at FRC volume reduces your apnea capacity during a full inhale or packing.
I believe it is because the 2,3-DPG level in your blood is modified and optimized for your lung volume. This controls the 'left or right shift' of the Hb-O2 dissociation curve.
I once did a hard phase of FRC training, and went to a competition and competed with inhale+packing. My performances were reduced compared to previously, even though my FRC performances were huge at the time.
The key way to watch or monitor this effect is simple. Upon starting FRC training, you will find that your FRC & exhale static times increase, and your inhale (or packing) static times decrease.
So, I think this effect would limit anyone who attempts to compete in one event with packing and another event at FRC, in the same competition. Personally I think that would be very hard to do.
eric,
i recently made a similar observation in my own training, but instead noticed a reduction of frc+static ability as inhale abilities increased.
over the winter, i trained repeated frc+static swims in the pool but in the last 3-4 weeks started doing 30min+ of inhale dynamics at the end of each session: approx 16x50m dynamic repeats---swim 50sec, rest 70sec continuous laps --- slow for many but breaking new ground for me.
as my inhale dynamic abilities increased (noticeably) each session and became my temporary focus, my frc+static swims seemed to get harder and harder. in a recent pool session i noticed a 20-30% reduction in frc+static ability (measured either by total dive time or distance), this effect i am assuming coming from the month of adding inhale dynamics to my training.
the reduction in frc seemed confusing until i read your post; i had initially hypothesized it to dietary changes, although i couldn't find any supporting data. through that period, i started taking a twice daily anti-inflammatory concoction to help ongoing knee and back problems: 1/2 tbsp fresh grated ginger, 1/2 tsp tumeric powder, and 1/2 tsp cayenne powder in warm water. the tumeric also helps mitigate gas/stomach issues associated with eating lots of legumes and pseudograins.
i had another personal frc observation regarding caffeine:
in my training experience, i rarely if ever get lactic legs as i am not training maximums but instead train frc+static repeats to mimic serial diving. prior to my last pool session, i took some added caffeine with my daily coffee in the form of cacao nibs; the added caffeine kick seemed to strengthen my dive response as my first few frc+static dives produced a much more uncomfortable static and then noticeably lactic legs in the last third of the swim. i may be off base, but this seems similar to sebastian murat's observations (in db posts) that his best frc+static dives, with associated strongest dive response, came when he started the dive with an elevated heart rate and anxiety. perhaps caffeine may have some benefit to frc diving in the form of strengthened dive response? but i wonder if the associated physiological effects are helpful overall?
cheers,
sean
vancouver, canada
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