Generally speaking, any successful endurance athlete is going to regularly include a wide range of intensities throughout their training cycle. The emphasis of their efforts will vary as they progress through their season, but they’ll still include some endurance training, some tempo and threshold workouts, VO2 max work, and anaerobic work, in order to maintain or develop their different energy systems.
The problem for some people is that they sometimes focus almost exclusively on 2 or 3 of those intensities and rarely, if ever, do much work at the other intensities. To a point, this can be okay, but for the best overall development, it’s good not to completely forsake a certain type of workout or intensity.
All too often, people will do the workouts they enjoy the most, and the workouts they enjoy are often the ones that feel the least difficult for them and the most fun. I’m all for having fun, but if you enjoy anaerobic workouts because you’re a good crit rider and that’s what you’re best at, or if you’re a good time-trialist or climber and you enjoy threshold workouts, that’s fine. It’s great that you either enjoy the intense pain of all-out 1-minute efforts or the long mental stress of pushing for 30-40 minutes on an extended climb at or just below your threshold. But, if that’s all that you focus on and never work on your weaknesses, you’ll be deficient in certain areas.
Most often, the workouts people fear the most are the ones they expect to hurt the most, and more than likely, are the ones they feel they aren’t as good at. I know that I don’t especially look forward to anaerobic workouts, and often rely on local races to provide that kind of workout, because it’s a little more fun and as a stage racer who’s best at climbing and time-trialing, anaerobic workouts seem to be less important to me. But, from talking with others and from knowing my own tendencies, sometimes it’s good to think about the kinds of workouts you’re afraid to do and ask yourself when you last completed a workout of that type. If you’ve been doing them every couple of weeks, good job. If you haven’t done a workout like that for a few months, then it’s probably worth considering when you could fit a few of them into your schedule. As long as you’re not in the down-time you set aside at the end of the racing season, including 2 or 3 workouts of that type each month will likely help fill a hole in your fitness, whether you’re a sprinter who needs to work on his staying power or a time-trialist who needs to work on her sprint.
Think about what you’re afraid of in training, and be sure that you plan on facing it on a regular basis. You’ll get a little extra mental toughness, and you’ll build a more complete fitness as a result.