Thanks guys for comments.
So this is what I got so far:
- to increase performance on the bike you gotta ride harder in whatever way until you reach a plateau. Only then you should start thinking about different and more specific training.
Basically...yes.
A fewyears ago I averaged 15.5 whatever the distance. I worked freekin hard over a season to up it to 18...and killed all the enjoyment once I got there, just busting a gut all the time.
Honk up hills where practical then ease up at the top to recover then pick up the pace again, that saves time lost going slowly uphill...and builds strength.
Don't be tempted to go straight off hard. On a 50 mile ride, it makes no difference if I start easy and warm up, or head out hard...I guess by warming up, you gain a bit later in the ride.
Hard hard work...and it's not always fun.
Ironically, having slipped back to 15.5average ( I'm 54 btw), I've been off the bike for 6 months of the last year, but frequently find myself averaging almost 17 mph without massive work on shorter rides. I guess that's mileage put in in the past, I was doing maybe 150 miles a week, gives you a good base fitness.