Wot he said. I think it would be correc to say that all mainstream grainy programs would recommend going much slower (80% zone2) with 20% in zone 5. Roughly speaking. Generally the mantra I hear is that us amateurs make the easy sessions too hard and the hard sessions too easy.
It's all volume dependent though. 4 hours of zone 2 a week with 1 hour of all other zones combined isn't going to make you much fitter. If you are doing big volumes (>8hours a week?), then it makes sense (and people who do big volumes often tend to have a high enough zone 2 that they can ride there without crawling up every tiny rise).
This, exactly.
It's not really correct to call zone 3 junk miles but there are some real cautions:
- Zones are not really well defined physiologically - heart rate percentages are actually quite variable, lactate levels vary dramatically by individual etc etc. With time and practice ventilatory thresholds are, I think useful, but these need to be learnt. Broadly I tend to place vt1 at the top of 'Z2' and vt2 at the top of Z4 in a 5 zone system. Vt's are well correllated with heart rate on an individual basis after allowing for fatigue.
- All zones (certainly 2 up) deliver training effects and all zones will improve mitochondrial activity etc (possibly excepting very hard short duration anaerobic work which we're not thinking aobut here)
- Unfortunately higher intensity training causes more fatigue (
no really Sherlock!) and high volumes will lead to overtraining, which is actually pretty bad, or need too much recovery between sessions
- so athletes wanting and needing to do regular and high volume training to extract the most they fair better on a diet of lots of Z2 and a (relatively) little proper hard work. The balance changes with season and periodisation.
If volume is low then proportionately more Z3 may well be OK or even more benificial. This is the basis of the 'sweet spot' programs that abound. My (personal) view is that these are either too low volume or too risky in terms of fatigue/overtraining to be optimal. Also, if you're at the upper end of such a program in volume terms you are likely to fair better on a diet of easier and harder (Chris' comment above applies).
Other considerations are that if you are building volume and fitness, Z2 is less likely to leave you injured and, as Duncan said, when you're fit it's not slow. The Tour peloton spends a lot of time in Z2 and they crack on though the countryside.
In terms of Z3, if your 70km ride took aobut 3 hours(?) that's a lot of Z3. A bit like running a marathon. You should be tired. Last summer I did a 3 1/2 hour Z3 run when I got a bit carried away and I could still feel it in my legs a week later.
Mike
Edited to add - and if you don't record heart rate (possibly and power) often your Garmin won't be all that accurate, as per L CC
