Revers Engineering Power?

Simple race day and long term goal settings is all about taking your goal and reverse engineering it.

  1. What power will you need on race day
  2. What threshold power will you need in order for you to achieve race day power


Bike Power Example:

A athlete looking to ride at around 75% of their FTP and is aiming for target time of sub 5 hours may need to hold 230 watts, giving this athlete a FTP of 310+ watts.


 Run Power Example: 

A athlete who is looking at running the marathon of the Ironman at 85% of their FTP with a target time of sub 3:30 may need to hold around 250 watts, giving this athlete a FTP of 295+ watts.


Starting Point

I am over simplifying things here as you will need to workout what power you need to ride to hit the goal time and is the goal power achievable within your time frame.  


Race Day Power

Just to give a starting point on race day power, here are some numbers to start with.  



  • Bike @75% of FTP
  • Run @85% of FTP (80% of FTP if weaker biker) 

Ironman 70.3

  • Bike @80% of FTP
  • Run @90% of FTP

Other factors definitely come into play when estimating estimated goal power like course, weather, power to weight, power to drag, etc.  Your training log will have a lot of the answers you are looking for.

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