Aerobic foundation is forms a baseline. It is necessary to complete the distance at a reasonable pace without a deterioration in health. Strength and force is a simple process: stress, recover, repeat. Biomechanic efficiency is the secret source to true performance.
Efficiency is the key
Ironman and 70.3 worlds qualification requires a run efficiency of 1.5 and bike efficiency of 1.7, numbers below will see you out of contention of scraping for roll down spots.
Efficiency is HR / Pace. Any poor biomechanics reduce efficiency, functional weakness reduces efficiency, unconscious incompetence reduces efficiency, a weak mindset reduces efficiency.
You can’t get to 1.5 and 1.7 by plugging away at a combination of volume and intensity alone, biomechanical efficiency has to be a focus too.
It’s about competency
There best way identify areas where you are unconsciously incompetent through specialist coach assistance or video analysis. This will place you with conscious incompetence. With the aid of coaching and focus you can move to conscious competence and then with more focus practice to unconscious competence and improved efficiency.
Get a technique coach, better still a specialist per discipline. Take a 6 to 8 week period every year to get pure on technique and balance functional strength, get to unconscious competence ready for the lead up to the next season.
Simple, effective, more a mental exercise than hard physical application.