Zone 2 training. A cardiac effect or peripheral muscle?

[chrisbainbridge]

Zone 2 training can produce big improvements in endurance at constant HR. Is this training the heart or training the leg muscles?

[Chris S]

Zone 2 training can produce big improvements in endurance at constant HR. Is this training the heart or training the leg muscles?

If your Zone 2 is equivalent to 180-Age HR, then that's Phil Maffetone territory; Aerobic base training done at such a low level, you can do massive volume without any risk of injury or over-training.

I spent a long time last year trying to ride a bike at these kinds of HRs - it's really hard, but very gradually, you get faster for the same low HR. I guess my HR is 10-20bpm lower at audax speeds, than it used to be.

It's such easy work - I can't imagine it builds any muscle as such.

[chrisbainbridge]

ChrisS, yes that is the zone I am talking about. I agree it does not build muscle.

I am really wondering if it is cardiac adaptation or leg muscle adaptation? 
Are you training the heart to pump more blood for a prolonged period or training leg muscles to work more with the same amount of blood?

[Kim]

Or changing the composition of the blood, so you don't need to pump as much of it...

[Pedal Castro]

... training leg muscles to work more with the same amount of blood?

This is pretty much the answer; increased efficiency in using glycogen, greater capillarisation, more myaglobin and mitochondria. So it'll make you fitter, but not faster; except that being fitter in itself will increase "cruising" speed and the length of time you can ride for etc.

The idea behind a polarised approach to training is that 80% should be in this zone and 20% should be HIIT sessions, which is the bit that makes you "faster".

[simonp]

I suspect zone 2 works most on peripheral stuff. Capillaries, enzyme activity. Perhaps a little hypertrophy of slow twitch muscle fibres.

Also suspect your central system responds more to vo2max work.

[trekker12]

Zone 2 training can produce big improvements in endurance at constant HR. Is this training the heart or training the leg muscles?

I spent a long time last year trying to ride a bike at these kinds of HRs - it's really hard, but very gradually, you get faster for the same low HR. I guess my HR is 10-20bpm lower at audax speeds, than it used to be.

How do you actually achieve this? I seem to spend most of my rides bouncing out into zone 3-4 without really trying.

[chrisbainbridge]

I choose flat routes with gentle inclines up and down. Accept that you will be slower and start with a couple of hours and build up.

I also do an hour on the turbo at a set HR adjusting power as necessary.

[Gus]

I suspect zone 2 works most on peripheral stuff. Capillaries, enzyme activity. Perhaps a little hypertrophy of slow twitch muscle fibres.

Also suspect your central system responds more to vo2max work.

+ improving your body to use lipids as a fuel.

[simonp]

For ourdoor riding in zone 2 I pretty much stick to riding around the Levels.

Riding a ride like Yr Elenydd or The Dean, it's not possible to stay there, particularly if I'm on fixed, but I try to keep HR down where I can.