Originally Posted by R600DuraAce
Get a power meter before you even try SST. You just can't use your HR for SST. You are constantly confusing Coggan's power zones with HR zones. When people training with power talking about l4, they are referring to sub threshold. Sub FT. Effort you can sustain for more than 1 hour. At l5 or zone 5, we are talking about 100% to 105% of FT. In another words, if you try to hold at l5 or zone 5 effort, you can't last for more than 1 hour. Zone6???? Vo2 max power. L7, purely AT (sprinting workout).
Uhhhh I'd like to meet the person who can go at L5 for more than 10 minutes, let alone 30, or an hour. L4 is your hour threshold, or FT.
According to Ric Stern over at cyclingforums, and Coggan as well:
Recovery
Zone1 Long Endurance 1.5-6hrs
Zone2 Core Endurance Endurance
Zone3 Tempo Training
Zone4 Long TT Power Intensive
Zone5 Shorter TT Power(and MAP/VO2Mx work)
Zone6 MAP training (VO2Max efforts) Maximal
Zone7 Anaerobic Work Capacity (<= 30s)