5'/4'/3'/2'/1' rest 1' between ladder intervals 2 mins rest before then 1'/2'/3'/4'/5' rest 1' Time interval completed in power zone 3 ascending/descending ladder. Targets descending are 75%/80%/85%/90%/95% rest 2 mins targets ascending are in reverse 95%/90%/85%/80%/75%