Hello, my coach has modified my training zones. In my case, it is a 5-zone model. Normally zone 1 and 2 are zones below the aerobic threshold (in my case it is so) but in zones 3 and 4 things change. My zone 3 is an area behind the anaerobic threshold and zone 4 and 5 are above, so, in the summary of training zones 3 models, there is some way to modify it to be Z1 (Z1-2), Z2 (Z3) and Z3 (Z4y 5). Best regards and thank you very much for the website!