Originally Posted by
chasm54
I've can attest to the fact that training exclusively at intensity has a negative impact on endurance riding. A few years ago I decided to race crits. I had been an endurance rider, I could easily cruise at 18-20 mph on flattish terrain with my HR around 120. For crits I switched my training almost entirely away from volume and onto intensity. It made me faster, alright, but by the end of that first season my endurance performance had collapsed, I could no longer cruise like I used to.
When you say intensity, are you talking all-out? Probably 1% of my riding is at breakneck pace, and in general, my average HR is no more than 140-145 on any typical ride (middle Z3). Sadly, I see riders who aren't all that fast who can ride all day long at Z3/Z4 pace, so I gather from that that riding at Z2 for long miles isn't necessarily the only ticket to getting fit or gaining endurance.