How hard is hard? Generally I will cycles as fast as I can physically maintain which is about 20mph or so on a flat. Any faster than this and I will have to slow down again because of my useless lungs. Does this count as hard?
If I get a tail wind or on a downhill I will cycle as fast as I physically can for as long as I can. This is definitely hard as im at maximum effort and my lungs are blowing up. Speeds can be anywhere from 30-45mph, for just a few seconds to a minute or so depending on how I feel or how long im in a slipstream etc. Do you have to feel bonked out at the end of a ride for the miles to count as "quality"?
Definitely not - in fact, I'd say it is counter productive. If I crack in a ride, usually because of a failed nutrition strategy, it takes a lot longer to recover and therefore subsequent days training are ruined. A banana every 20 miles is my rule of thumb. You don't need to go flat out either, depending on aims(the shorter the time you have available, the harder you should ride). Feel free to slow down in your rides to recover from the harder efforts as well. Following the layout I set out above, if you ride the 90 minute sessions at a tempo pace, that would be fine (tempo meaning laboured breath - and judging from your speed of 20mph, 17-18mph). Once you've been putting in good miles for a month or two, google HIIT (High Intensity Interval Training) or SST (Sweet Spot Training) - or come back and ask on here. Sounds like you are pretty nippy though, so keep doing what you are doing, so long as you aren't wrecking yourself 7 times a week.
I'd also like to point out, I am no expert, just a keen racer who has tried and tested a few different systems of training. My main advice to anyone looking to make gains is not to concentrate too much on the science of training - you can get lost in it and end up using prescribed training methods to slack off. Just ride you bike and get quality miles in.
Quality miles:
- a hilly ride is quality miles
- structured efforts, e.g. timed routes, sprints, recovery rides when adequate....quality miles
- adding a 2.5 miles commute to your mileage total....not quality miles
- riding along a canal path whilst walking the dog - not quality miles
- riding your town bike to post a letter - not quality miles