Originally Posted by
chaadster
I really don't understand when people talk in the language of Power based training but without power numbers. I just can't seem to translate from the specificity of power down to the loose, ballpark-it realm of "going by feel." Maybe--hopefully-- it makes sense to you guys, but I just can't tell what's being said or how it's being assessed. I'm kinda surprised it works at all, to be honest.
Go by breathing. That is a good measure of oxygen consumption until panting starts. Then it's a measure of CO2 removal.
Zones, whether figured by power or heart rate are based around the effort one would use to ride hard steadily for 1 hour, finishing by falling off the bike in complete exhaustion. Heart rate based, it's called lactate threshold (LTHR). Power based, it's called functional threshold power (FTP). Whatever it's called, it's when you're breathing as fast as you can while still breathing deeply. The ability to keep this up for a long time, up to an hour, is a result of a terrific amount of hard and consistent training.
Further:
Z1: breathing deeply but slowly. Starting to sweat a little. Easy to ride all day.
Z2: breathing deeply and steadily. The top of Z2 is when you notice that your deep breathing rate is starting to increase more rapidly. A conditioned cyclist can ride for hours at this pace.
Z3: breathing deeply and fairly rapidly, tiring but not going hard enough to exhaust one in the near future.
Z4: breathing deeply and quite rapidly. Pain in legs begins to increase from lactate buildup. 20 minutes is a long time at this pace.
Z5: Over LTHR and FTP: panting. Deep breathing no longer possible. This is the start of anaerobic effort. You're not burning much oxygen to get energy. Instead, you're panting to try to get rid of CO2 buildup. 8-10 minutes is maximum.
The boundary between zones 3 and 4 is ill-defined and somewhat arbitrary. Zone 3 is an area where you tire yourself but aren't going hard enough to get a good training effect.