Xert’s Three Systems

From this excellent blog on polarized training I understand that Xert doesn’t use the traditional (FTP, HR) zones, however, uses focus and three systems peak, high and low energy to quantify training strain.

What is the relationship of these three systems to what happens physiologically? For instance, can I link them to muscle types, e.g.:

  • Low Energy = using predominantly Type I muscle fibre
  • HIE = using Tpye IIa
  • Peak = using Tpye IIx

Or is this just a coincidence?

Thank you,

1 Like

See http://baronbiosys.com/the-science-the-physiology-behind-focus-and-strain-and-how-to-train-the-metabolic-pathways/ section " Relationship to Fitness Signature".

So yes it corresponds.


Many thanks for answering my question.