Originally Posted by maydog .
My thought is that any intervals at or above your goal pace is good.
Yup.
Keep it simple, stick to the basics. 2 "interval" days a week is fine for most people. It's good to be properly warm before starting.
Try a 15 or 20 minute interval at an effort of around 80% of your MaxHR. Try to keep the effort steady and do what you can to avoid interruptions like traffic lights and stop signs. Since the effort we can put out changes based on our fitness relative to HR, one way to think about it is to do these at the intensity right before you start accumulating lactate. Some describe this right below TT pace. Rest between sets would be easy/normal riding for 10 minutes before the next interval. These help bump up your FTP and cruising speed. I like doing 2x20 once or twice a week. After awhile you can increase to 30 minutes, or more. Many folks do these year round.
Shorter, more intense intervals also go a long way to building fitness. A few reps of 3 minutes at around 90+% MaxHR. When I'm doing these types of intervals I usually do 3 or 4 "reps" of these with around double the rest. So for a 3 minute interval, rest for about 6 or 7 minutes. The key to be these is to be fresh. Pedaling between reps while resting should be easy going. If you need to rest even a few more minutes go for it. These are hard and unpleasant... good for racers, good for masochists. If you have trouble completing the full set, you probably went to hard. It takes some time to learn - you are teaching your body a new skill, basically how to operate at redline. After a couple weeks add another rep or two i.e. 4x3, 5x3, etc. I never really do more than 4 or 5 of these hard efforts during a workout. It's better just to add a whole additional set with a bigger rest separating the two sets. I.e. 2 (3x3min) with say 10 or 15 minutes between the two sets. One cannot really go by HR on these, especially at the beginning of the effort, as it will usually take 30-60 secs for your heart just to catch up and then you may realize you started to hard. Better to air on the side of caution and then just go harder on the next rep. To be honest, unless you are racing I may just focus on the 15 and 20 minute efforts. It's been said a few different ways but if you don't find Jesus in this workout, you probably went too easy. Even the folks who do these usually limit the big training blocks to 2 or 3 months before taking a substantial break.
There's an even shorter flavor - 30 secs on (or something less than one minute), 30 secs off. repeat ad nauseaum. This is a final sharpening tool to help the body adapt to processing frequent lactate accumulation and the repeated attacks in the closing stages of a race that is usually only done in the tail end of a structured interval plan. There are better ways for a recreational cyclist to spend their training time.
There is a lot of information out there and many people have different ways of doing things. This is just what I have settled on that seems to work for me. But one thing holds true regardless - be consistent, otherwise there's not much point beyond doing them beyond the "enjoyment". Think of weight training in a gym, ***** nilly workouts here and there may be fun but they don't do much, but consistent workouts that build on prior workouts, and slowly add work do.