A bit of background first: I'm pretty disgusted with my performance in the other sport/physical activity in which I participate . . . tennis. So, I started up taking weekly lessons again, about a month ago. A pattern has developed during the lessons, and I talked about it with my coach tonight. During the lesson, as he is feeding balls to me, I get out of breath after about five-ten minutes and have to take about a half a minute or so to recover. He says that my anaerobic conditioning is lacking, but that with my cycling, my aerobic condition in fine. (I question the level of my aerobic conditioning, but I wasn't going to debate the point with him.)

I asked him how to build up my anaerobic endurance, and he said, "intervals". Since some of our family members here raced in the past, (and some still do), and some of us have ridden "intervals"; I'd like to ask, How would I go about riding intervals on a bike?

Scenario: I live in an area where I can be out in the sticks in about two-three miles. The roads outside of town are all straight in a north/south and east/west orientation. There is a stiff prevailing wind in the afternoons from the west or southwest. Outside of town, in the desert, I can ride a minimum of one mile without having to stop at a stop sign. On some of the roads, I can ride up to several miles before having to slow down/stop at a four-way stop sign. One road, which is very heavily traveled, and I really don't want to ride on that road, is probably eight/ten miles before having to stop for anything.

This is on the flats, (valley bottom). There are hills about, also within a very few miles. The closest hill is two miles in length and the back side is only one mile in length. About a 4.5-5% average gradient with a few ramps around 10%. Other hills are longer, one is very short, but also very, very steep, (the one time I tried to ride up it, I couldn't make it to the top before having to dismount).

I do not have a MTB, just road bikes, (and a TT bike which has not been fitted to me yet). Last limited parameter is my work schedule. I have to rise every morning at 4:15 to get ready to catch the vanpool for work. This is M-TH. We are on a 9/80 schedule. Since I'm bumping up against the limit of how much vacation time can be accumulated, I usually take every Friday off, either as the RDO, (Regular Day Off because of the 9/80 schedule), or as a vacation day. In a few weeks, I start teaching two nights a week, (M and Th), and currently have my tennis lesson on Tuesday evenings. This schedule means that the only time I'll be able to "do intervals" is on Wednesdays and my three-day weekends. I expect I'll be told that this frequency won't be enough to build anaerobic conditioning.

So, how do I ride intervals on my bike? Are the intervals based on time or distance? I appreciate any advice/help anyone can offer.