Quote Originally Posted by Cassandra_Cain View Post
L4 is a power zone which ranges from 91-105% of the power I can produce for one hour. Doing intervals @ L4 is a great way to increase your sustainable power. In simple terms, it means you go faster, for longer. As an aside it also raises your Lactate Threshold, letting you work at a higher percentage of your aerobic capacity.
Oh MY! you can ride up hill for 20 minutes at a crack? I'm impressed! OR maybe I'm just doing it all wrong yet, and will get the hang of it.... So, this L4 power level -- it sounds pretty challenging, like, if I can ride at say 15mph for an hour on the flats, to ride close to that on a hill for 20 -- that ain't happening, maybe until I'm 80. I guess one starts small with this, but the concept is intriguing! (or I'm slightly nuts)

Karen in Boise