Using my Fitness Signature

Hi, I started using Xert because I like the multidimensional nature of it. The concepts of peak power and threshold power are easy to understand and see the impact because they are easily translatable to w/kg and then easy to see impact on climbing, sprinting, etc.

However, I’m struggling to understand HIE. I have a good feel for what my TP sitting at 320 or 360 may mean for performance, but I don’t really have any concept of HIE other than a bigger number will mean (I think) I’m better and doing, sustaining and repeating efforts above my TP without blowing myself up.

Can someone help me interpret / understand? I’m trying to determine what number I should look to build towards and if I achieve (eg) an HIE of 28 how do I translate that into a performance gain?
Two target events - one a 40km time trial in July, the other a 130km road race in September with 2 decent climbs.
PP 1136W
HIE 26.1kj
TP 362W


Hi Greg. It isn’t possible to focus on only one dimension of your fitness. Every pedal stroke can involve all three simultaneously. Focus is the metric that you can use to understand this interaction. Look at our glossary on work allocation ratios to see how this all fits together.