When you start training after some time off, you likely need a few months to work on increasing your fitness before training more intensely for race season. This period of building fitness is often called the base period since you are establishing a foundation of fitness that, like a pyramid, you eventually polish off to a peak of fitness for your goal race.
This basic template of building fitness and getting more specific as race day approaches, called periodization, can be manipulated in a variety of ways and generally holds as sound practice. However, periodization in cycling is not without myths that can be limiting especially if you have limited time to train or are lacking early exposure to the sport.
While establishing your base of fitness, a traditional practice is to do lots of long, slow distance work. Regardless of how much time you have, it is a mistake to avoid speed work and interval training. Instead, aim to include things like sprints, high and low cadence work and even some maintenance work around race pace.
A second concern for the busy athlete working full-time is base is about gradually accumulating training load (e.g., intensity x volume). If you have limited hours, you will eventually not be able to add hours to your week, so you must start including intensity. It is very common in the base phase to include 2–3 days of moderate intervals (e.g., tempo intervals around 80–85% max heart rate) to further your fitness accumulation.
When crafting a training plan or while following one, it is much simpler and more familiar for cyclists to only do on-bike workouts, but this is a mistake. The base period is the time you can and should be in the gym building your strength and working on your movement limitations (e.g., what hurts? What movements can’t you do?). It is also beneficial to pursue cross-training to mix up your mental and physical loads.
Whether you train indoors during your base season or not, it is important to work on elements of coordination. To improve your pedal stroke focus on tasks you can easily see progress in rather than computer readings or using specific muscles. Clipping one foot out and pedaling with one leg is a classic pedal stroke drill that is easy to see progress in over several weeks. Interacting with your bike with only three limbs can be a good practice in itself, not to mention the practice of clipping in and out.
More practically, riding on a variety of surfaces (e.g., snow, sand, mud, gravel) gives you immediate feedback on your pedal stroke and position. Outside you must shift your position and vary your pedal stroke dynamically with the terrain. While indoors, use drills that mix up your cadence (high and low) with a moderate-to-high effort to prepare you for the variable workloads and cadences required outdoors.
While the term ‘base’ is synonymous with winter training, a base or ‘accumulation’ phase can be done at any time during the season. If you require more fitness, then you can qualify your training phase as ‘base’ and limit racing in favor of accumulating fitness. For winter bound athletes or cyclocrossers with races later in the summer or into the fall, this may occur in the spring, which is great because you can do your big rides in much nicer weather.
In the discussion of training methods, the concept that most athletes train for fun and do not get paid to ride is ignored. Base training should not be associated with misery or boredom. You can ride the cycling discipline you love (weather permitting), long rides should ideally be done with a friend at a conversational pace and indoor rides should include enough structure to keep you engaged. Cross-training should be pursued to avoid too much indoor trainer time, which is draining no matter how many screens you use. Spending time in the gym or yoga studio ensures you are accumulating fitness in an effective, fulfilling and sustainable way.