If cyclists want to improve their performance and endurance on a road bike, mountain bike, or gravel bike, it makes sense to train according to a plan. The basis for this is to know one's own performance capability. Athletes often use simple models that work with easily measurable parameters such as heart rate and power. In recent years, however, precise watt measurement systems, which were previously only available to professionals, have increasingly established themselves in the amateur sports sector. At the same time, service providers offer performance diagnostics that help determine your own performance capability through lactate step tests and spiroergometry, and then improve it through individual training and precise control. To manage this process, professional cyclists often have personal trainers who create and adjust their individual training plans. Of course, athletes can blindly follow this advice, but it is helpful if they understand their training plan to implement it successfully. The training zones help with this understanding. 

In sports science, there are various models for dividing training zones. In the German-speaking world, a model with five training zones has established itself for endurance sports, especially in cycling:

These training zones are often indicated as percentages of maximum heart rate or by watt values. Since each person has individual performance limits, it’s important to know your own training zones precisely. A precise method for determining this is a lactate step test on a cycle ergometer. Another option is to determine the maximum oxygen uptake (VO2max). Such spiroergometry is usually reserved for ambitious or professional athletes due to the relatively high costs, to complement lactate analysis.

As mentioned earlier, the training zones in cycling serve to control training specifically and address the various physiological systems of the body. This can mean, for example, the pumping capacity of the heart, the branching of blood vessels, the number and efficiency of energy-producing enzymes, or muscle strength. By dividing training into different intensity zones, athletes can specifically work on certain individual aspects of their performance. The main goals of the training zones are: 

1. Improvement of Basic Endurance 
Basic endurance forms the foundation for aerobic performance, i.e., the ability to maintain moderate exertion over long periods. Training in the basic endurance zones (BE1 and BE2) primarily increases the efficiency of fat metabolism and the capacity of the cardiovascular system. This is a fundamental ability for all endurance athletes, but especially important for cyclists who cover long distances and want to create a solid foundation for more intense exertions. Practically speaking: Efficient fat metabolism conserves carbohydrate reserves for crucial hard phases. 

2. Increase in Load Tolerance
Through more intensive training zones, such as the development zone, the anaerobic threshold is shifted. This means that the body is adjusted to produce less lactate at higher intensities, or to better cope with a certain concentration of lactate in the blood, thereby increasing fatigue resistance. This is crucial for cyclists who need to maintain consistently high intensities in the aerobic-anaerobic transition zone over long distances, such as in time trials or in the mountains. 

3. Improvement of Peak Performance and VO₂max
The high-intensity peak zone trains not only maximum oxygen uptake (VO₂max) but also speed. This is important for short, very intense bursts, such as sprints or fast climbs, during which 100 percent performance must be delivered for about 20 seconds, which can easily be 1000 watts even for amateur athletes. 

4. Optimization of Recovery
The compensation zone serves active recovery. It is important, for example, between intensive sessions or when athletes do not feel absolutely fit. Light rides in this zone promote blood circulation in the muscles and accelerate the breakdown of metabolic products that have accumulated during more intensive sessions. Training in this zone reduces muscle soreness and helps prepare the body for the next intensive session. Due to the low intensity, overloads and injuries are avoided while promoting recovery. 

5. Structured Training Control
Training zones simplify the planning and control of training. They enable athletes and trainers to set specific goals for each session, work on individual performance components in cycles, and make it easier to measure progress and make adjustments. The different zones help athletes develop a better understanding of their individual load capacity and regulate intensity more effectively during training. This leads to more efficient use of training time and optimal performance improvement in the long term. 

In summary, the training zones enable individual, targeted training design that covers the most important components of performance in cycling. They ensure that athletes achieve higher performance both individually and globally in a shorter time and with less effort. They also enable targeted work on weaknesses. The prerequisite for these performance improvements is also the aforementioned regenerative training sessions in the compensation zone. 

Not all athletes have or use the opportunity to undergo professional performance diagnostics. Against this background, the FTP value (Functional Threshold Power) has recently gained popularity because it is relatively easy to determine. This performance test can be easily done alone at home on a roller trainer. Cycling training platforms such as Zwift offer pre-made programs for this purpose. The FTP describes the power that athletes could maintain over an hour, often referred to as CP60 (Critical Power 60). In practice, however, the FTP value is usually determined via a CP20 test, where the power is measured over 20 minutes and then extrapolated. This test is only meaningful with multiple comparison values from several such tests, as individual factors and experience play a significant role. Note: The shorter the load phase from which the FTP is derived, the less reliable the value. Additionally, the FTP value, as mentioned, is only a calculated value and does not provide insight into the physiological processes in the body. It can serve as a rough guideline but should be regularly checked under identical conditions. A lactate step test provides significantly more reliable results.

The division of training zones in sports science is based on the different types of energy provision or their combination. Depending on the intensity, the body uses different mechanisms, with a fundamental distinction between aerobic (with oxygen) and anaerobic (without oxygen) energy provision.

1. Compensation Zone (CZ) 
The compensation zone serves active recovery and is ridden at very low intensity and usually high cadence. The heart rate is below 60% of the maximum heart rate (max HR), and the load is low enough to promote recovery while simultaneously stimulating blood circulation in the muscles. CZ sessions help recover from more intensive sessions and ensure better adaptation of the body to training. 

2. Basic Endurance 1 (BE1) 
In the BE1 zone, training is done at about 60-70% of the maximum heart rate (max HR), which represents moderate exertion. This zone is the foundation for endurance capability and is used to improve aerobic capacity and promote fat metabolism. Long rides in BE1 are particularly important for preparing for longer races or endurance events, as fats are a scarcely exhaustible energy source of the body, while all other sources are stored in very limited quantities. 

3. Basic Endurance 2 (BE2)
 In the BE2 zone, the intensity is slightly higher, about 70-80% of the maximum heart rate (max HR). Training in this zone increases aerobic performance and shifts the threshold at which the body increasingly relies on anaerobic energy production. BE2 training is often used for sessions that are somewhat more intensive than pure basic training and where the body is prepared for moderate loads with an energy mix of fats and carbohydrates. This depletion of carbohydrate stores also results in their capacity being expanded. This allows one to maintain a high pace longer later. 

4. Development Zone (DZ) 
This is the transition zone between aerobic and anaerobic energy provision. The load becomes more intense, and the training time is shorter. Anaerobic metabolism means that almost exclusively carbohydrates are consumed  alongside an oxygen debt. Lactate production and lactate breakdown are no longer in balance; more lactate is produced than can be broken down, the lactate level in the blood rises. Training in the development zone leads to higher stroke volume and improved muscle blood flow; the muscles become more efficient and are supplied with blood and oxygen up to higher loads. In the long term, the VO2max value increases. Typically, training in this zone is done at 80-95% of the maximum heart rate. Of course, these training sessions are shorter but specifically aimed at improving load capacity. Due to the high effort, the repetition or interval method is generally used, incorporating several cycles in the DZ zone into a BE1 training. 

5. Peak Zone (PZ) 
The peak zone is the highest intensity zone and corresponds to about 95% and more of the max HR. The body is brought to its performance limit for very short intervals. The body creates a larger acid buffer, so metabolic processes continue even at lactate concentrations where an untrained person would have had to stop long ago. Thus, the VO2max and explosive power are improved. These sessions consist of short, high-intensity intervals followed by longer recovery phases. The peak zone is often used in preparation for competitions to train anaerobic capacity and explosiveness. According to the latest findings, a rapid sequence of such submaximal intervals with rather short breaks even has positive effects on long-term endurance. This is referred to as "HIIT" or High Intensity Interval Training.

The five training zones mentioned above allow for structured and targeted training as well as long-term form building, which is beneficial for both beginners and experienced cyclists. A well-structured training plan should include all these zones in a balanced ratio. In doing so, the hard sessions gradually replace the long and sub-threshold ones to optimally prepare the body for the specific demands of cycling or a specific athletic goal in cycling.