Originally Posted by
work4bike
This is where we get into the very gray area. What's too easy? I could go for a run or a ride at a ridiculously slow pace and yes that will not add to my cardio/muscular benefit. Although, you could make a point that if anything it will add to other things, just one example, toughening up the butt, but other things also that become sore from cycling. Not a big issue for those of us that have been cycling for years, but this is very important things to build up for newer riders.
However, when I said "easy rides", I wasn't thinking of ridiculously SLOW rides, simply because most of us find it too difficult to do ridiculously slow rides. I would guess most of us would obtain at least 60% max H/R during an "easy ride". And that is money in the bank. Just watch the video I posted above and here's another one by the coach Jack Daniels. If nothing else, easy rides (not ridiculously slow rides) allows the body to recover and at the same time provide cardio work.
Z1 is too easy. It doesn't have anything to do with speed. I can do 180 watts in z1 and still average 18-19 mph, but that doesn't mean I got anything from that ride. And if such a ride comprised a good chunk of my regular weekly riding, not only would I not gain fitness, but I'd lose it.
The kicker with hr is the amount of variance it allows in power output. You may average 60% max hr but coast or soft pedal for 30 minutes of a 2 hour ride (so lots of "junk time") and not even have a big change in hr (the unfitter you are, the higher and longer your hr is likely to remain elevated). Examining power output makes a big difference.
In any case, comparing hr across both running and cycling really isn't that applicable. You're not getting all of those breaks when you run that most people are getting in riding.