The 70.3 distance sits in a unique spot that exposes specific training and racing errors. These three mistakes are among the most common - and the most fixable.
1. Over-Training the Bike, Under-Training the Run
In triathlon, the run has the highest correlation with finishing position. The 70.3 is the epitome of this. With many high-performing age groupers already riding in the mid-to-high 30 km/h range, gaining speed on the bike becomes exponentially harder due to the nature of air and rolling resistance.
Going one kilometre per hour faster at 30 km/h requires far fewer watts than doing the same at 40 km/h. In most cases, it would be much easier to make up that time on the run - if you have actually trained for it.
Consider upping your run volume and reducing your bike volume. The time you gain on the run will almost certainly outweigh what you lose on the bike. If your run is the weak link, check whether any of the common mistakes ruining your run split apply to you.
2. Not Building a Speed Base
Speed is the base of endurance, not the other way around. There is a reason short-course athletes consistently outperform long-course specialists over the middle distance.
Instead of spending every training block focused on base building, try incorporating a speed development phase before moving into 70.3-specific work. A higher top-end creates more room below it for sustained race-pace effort.
3. Overdoing Your Race Nutrition
In the Ironman, nutrition is still reasonably important - just not as important as most people think. In the 70.3, you almost certainly need far less than you believe.
A cramped gut from taking on too much nutrition will cost you far more time than being slightly under your fuelling targets. If you are experiencing gastrointestinal issues during racing, try reducing your intake rather than increasing it.
Unless you are taking well over six to seven hours for a 70.3, loosening up your nutrition strategy may be the simplest performance gain available to you.
Bike for show, run for dough. The 70.3 is where this matters most.