Great news Pierre. Congratulations on your accomplishment and the smart and thoughtful approach you used. Simpler is better, as you've learned.
By simple, I mean:
1. Cultivate (traveling 60% or more of height on each arm stroke while in the pool), relaxed and efficient stroke. How long? Use the TI Green Zone to calculate the SPL that lets you travel 60% or more of your height on each arm stroke.
2. When that stroke length feels comfortable, familiar and consistent, then focus your practice on two things
(a) Continually make small refinement to efficiency and 'encode' them in your brain so your best pool form becomes resistant to breakdown in the situations you encounter in an open water swim leg; and
(b) Patiently adapt your neuromuscular system to small increases in tempo and/or distance--while maintaining the inherent efficiency (distance traveled and ease) of your stroke.
You did that and in 20 months progressed from swimming only 15m to swimming 3800m in the top 30% of an IM field.
How many people (outside of TI) can boast of such fantastic progress?
Head Coach & Chief Executive Optimist
May your laps be as happy as mine.
My TI Story