This higher intensity in the "non-race" season might just work ... due to a decrease in my available training time, the coach I work with has had me doing "base" at a higher intensity than typical. I train with an HRM - she has me riding in hi zone 2/low zone 3, which falls about 20 beats below my lactate threshold - and has me doing near threshold and threshold work (Z4 and Z5 in the form of cruise intervals and big gear/muscle tension intervals) as well as stomps, power starts, and spinups at short high iintensity. I've still been getting 3+ hr. rides in on weekends and totaling about 9-10 hrs/week on the bike time, running 1 day/week + a core day and consistent stretching.
I've been feeling very strong and did a VO2max test on sunday, the kind where you're hooked up to a computrainer with a respirator and tubes on and the coach amps up the wattage until exhaustion, and my power at threshold was 20 watts higher, with weight 3# lower than the last test I did in november.
I try not to get too wrapped up in numbers and technical stuff, that's one reason I have a coach, but the point of this rambling - which I realize is not new information - upping your intensity during endurance rides and keeping some near threshold and threshold work in your offseason program appears to pay dividends. I just hope those dividends are still there when we actually start pinning numbers on and improvement continues through what is a long race season. I definitely have concerns that I'm burning a few matches that might be needed in August, we'll see.