There's a great disparity between the way coaches advise triathletes to train on the bike in columns such as this one and the way most triathletes actually train on the bike.
The majority of articles on bike training for triathletes focus on higher-intensity workouts such as threshold rides, VO2 max intervals and hill repetitions. The authors of these articles (myself included) are well aware of the fact that, as endurance athletes, triathletes should spend most of their time training at a steady aerobic pace. But this type of training is not quite as interesting to write about as the higher-intensity stuff, so we overemphasize the higher-intensity stuff.
The average age-grouper does few or none of these workouts, however. Indeed, the variable of intensity is not really a variable at all in the training of the average age grouper. Every ride is done at more or less the same effort level. The only factor that distinguishes one workout from the next is duration. "Let's see: Should I do my 45-minute loop, my one-hour loop or my 90-minute loop today?" Oh yes, I'm on to you!
We triathlon coaches must not fool ourselves. The average age-grouper's willful avoidance of intensity manipulation in bike training is not the result of lack of information. You folks read our articles. It's really a matter of sheer stubbornness.
These fancy high-intensity workouts seem to require that you do all kinds of logistical preparation, find the perfect training environment (your favorite one-hour loop surely will not do) and control and monitor your power output, heart rate, speed, cadence, interval distances and split times with scientific precision.
You figure you get 90 percent as much fitness benefit from noodling through your favorite one-hour loop at a steady, moderate effort level time and time again as you would get from throwing some fancy high-intensity workouts into the mix. You reckon that the hassle you spare yourself by not doing these workouts is worth more to you than 10 percent greater fitness.
So you keep doing your loops.
I would like to propose a compromise. Your bike training does not have to be all or nothing—your way or the coaches' way. With just a little mental effort you can easily incorporate some valuable high-intensity training into the same old routes you ride two or three times per week.
By making this small effort you will get a significant boost in cycling fitness without adding any extra logistical stress or planning hassle to your routine. Here are four specific workouts to try:
1. One-hour Loop With Threshold Work
Threshold intensity is more or less your 40K time-trial effort level. Training at this intensity will improve your performance not just in triathlons featuring a 40K bike leg but also in triathlons of every distance because it produces physiological adaptations that generally improve your capacity to sustain hard efforts.
To turn a one-hour loop into a threshold workout, just throw in one or two blocks of riding at your known or estimated 40K time-trial power level/speed. Don't worry about the effect of turns, winds and hills on your speed. Just maintain a consistent effort level.
Be sure to begin the workout with at least 10 minutes of easy spinning to warm up. Beginners should do no more than 10 or 12 minutes of threshold riding in their first session. If you're fit and competitive, you can build up to 2 x 20 minutes, or 40 minutes straight. (Note that doing a given amount of threshold riding in two equal blocks instead of one block is always a little easier.)
As you gain fitness, your threshold power level/speed will gradually increase. Allow this to happen automatically, rather than forcing it, by always riding at the same subjective effort level.
2. One-hour Loop With VO2 Max Work
VO2 max intensity is approximately the highest work level you can sustain for 10 minutes. Training at this intensity produces big gains in aerobic capacity and fatigue resistance at very high effort levels.