Interval Variable. 5'/4'/3'/2'/1' rest 1' between ladder intervals 2 mins rest before then 1'/2'/3'/4'/5' rest 1' Timed targets descending are 75%/80%/85%/90%/95% rest 2 mins timed targets ascending are in reverse 95%/90%/85%/80%/75% ⚠️ Advisory. 8’ gradual warm up hitting 3-4 bursts at Z4. ⚠️ If targets are a stretch start 5-10% lower (your mind and body will thank you for it)