Training with Intensity in December?

From a recent post in Cyclingnews.com by former CSC professional cyclist, Bobby Julich, "...I used to do long, slow miles as a way of building up my endurance. But I believe that mixing in some intensity during the off-season, especially focusing on your weaker areas, can be a big benefit. I think that it is a good idea to ride with others or even big groups. It is a great opportunity to meet new people and stoke the competitive fire again..."

I agree.
My old coach Donny Quixote started me on the right path by including some intensity, even in my fall base periods. I have taken that principal and adopted it into my current program.

I recently sent one of my workouts to the team. One of my mates questioned the zone 4 & zone 5 stuff in the plan. Here was the workout:

10m warm-up, then:

Z2 5 minutes

Z3 5 minutes

Z4 5 minutes

Z5 5 minutes

Z1 15 minutes

Z3 90 minutes

Cool down

My response was to him was: this week I will train approximately 20 hours. That's 1200 minutes - 10 minutes above Z3 and 1190 minutes at Z3 or less (maybe a few more minutes of intensity during weekend rides in the dirt - especially riding with Pistol Pete).

When you look at the overall effort for the week, it is still well within the endurance category, yet I have not completely let the higher intensity systems atrophy.

I find that if I maintain at least minimal connection to my entire range of fitness, when the time comes to begin adding back in the intensity, I am not in quite so much pain, and can deliver the big wattage for the entire duration of the interval.

The more I read, the more I hear other successful road cyclists taking a similar approach.