Training metrics in endurance sports: heart rate, pace and power

What exactly are the training metrics?

Training metrics are based on individual threshold power - the load that a person can maintain over the course of an hour. This threshold power forms the basis for defining individual training zones (Allen & Coggan, 2015). It is important to note that threshold power alone cannot provide a complete insight into an athlete's metabolic profile. With spiroergometry available, the training zones can be defined even more precisely in Enduco.

The correct recording of current performance data is essential. In order to obtain reliable results, a consistent test method is required - for example, a standardized performance test by Enduco. This prevents deviations in the individual test results. An incorrectly estimated threshold performance leads to incorrect training analyses. If the threshold is set too high, the actual training load is underestimated; if it is too low, it is overestimated. This has a direct impact on long-term training control. If you are unsure, you can contact our support team at any time - we will be happy to take a closer look at your profile!

Heart rate, pace, power and RPE are the most important training metrics. They form the basis for other values such as training load, fatigue level, fitness and fatigue. The training load makes it possible to quantify the training load (internal and external load).

How the training metrics differ

Each metric reacts differently to stress during training:

• Heart Rate (HR): HR is an internal training metric and is very sensitive to external factors such as heat, altitude, nutrition and hydration. It increases with sustained exercise, but responds with a delay during breaks in exercise. It best reflects the actual physical exertion.

• Pace/ speed: Pace/ speed: This is an objective training metric. The pace changes depending on the profile and ground conditions.

• Power (watts): The power measurement shows the objective load in real time. When cycling, the power remains relatively constant on a climb, while it is close to zero on a descent.

• RPE (rate of perceived exertion): On a scale of 1 - 10, the subjective state of well-being is assessed. This is an internal training metric and behaves in a similar way to heart rate.

These differences are crucial for choosing the right training control and evaluation.

Fig. 1: Training metrics and their behavior during training (Ferrauti, 2020, p. 392)

Which training metric should I favor?

The choice of the right training metric depends on several factors: the athlete's experience and performance level, the ambient temperature, the topographical conditions, the available financial resources and the duration of the workout - for example during interval training (Hanakam & Ferrauti, 2020). Heart rate is generally the best training metric, provided it is measured correctly, as it is the most accurate reflection of physical exertion.

• Basic endurance training: Heart rate is the best choice here, as it ensures that you stay in the aerobic zone and do not train too intensively without realizing it. Heart rate is also the best metric for measuring intensity on the trail.

• Tempo and threshold intervals: Heart rate is also the best choice here, as it is an interval intensity that should hit the metabolic threshold. As the heart rate also reacts to external circumstances, it is easier to measure the actual strain on the body.

• High-intensity interval training: Power or pace (running) are the better control variables here. Heart rate lags behind the load and is therefore less suitable for fast, short intervals and the associated training control.

If you do not have heart rate, pace or power values available, it is all the more important to enter your subjective feeling of exertion directly after the session in enduco.

Measurement method

• Heart rate measurement: The accuracy of the HR measurement depends heavily on the method (Stössel, 2019): A chest strap provides the most accurate data and is the best choice for reliable heart rate measurements. Wrist sensors, on the other hand, can be inaccurate, especially with rapid changes in load or cold temperatures.

• Watt measurement: It is important that you calibrate your watt measurement before a performance test so that you have a very accurate measurement. If you have several bikes with different watt measurements, you must bear in mind that the different measurements can lead to different results

• Pace measurement: Depending on the provider, the GPS recording is more or less reliable. Watches with "dual-band GPS" offer better accuracy, but usually cost a little more. Take a look at your pace stream from time to time, if there are "outliers" here, this can have a major impact on your training load calculation.

Why a combination of metrics makes sense

Although each metric has its strengths and weaknesses, they are closely linked. For example, a pace-controlled unit always correlates with heart rate. For the best training control, the objective load values (pace, power) should always be compared with the internal measured values (heart rate, subjective perception of load). This combination enables a holistic analysis and optimum training control.

Ultimately, you should always pay attention to your own body feeling, as no metric can completely replace this. It is also important to recognize whether your training parameters are set correctly, which is why regular performance tests are also useful. Good nutrition before and during training is essential. Sometimes it can make sense to shorten a training session, especially if it is done indoors on the roller or treadmill instead of outdoors. The important thing is not to achieve a certain training load, but to tailor your training to your individual needs. enduco will then adapt your current plan so that you can still achieve your goal.

Conclusion

Choosing the right training metric depends on several factors. While the HR measurement is a valuable control variable, especially in basic and speed training, power and pace are often more precise for short, fast interval training. The quality of the measurement is also important - a chest strap offers the best results here. The optimal control of training ultimately results from the intelligent combination of all relevant parameters.

Regular monitoring is essential in order to analyze the athlete's reactions to training and make informed decisions about training and recovery measures (Halson, 2014). It is important that the training load is not considered in isolation, but always in conjunction with the duration of training and the time spent in the respective load zones. In addition to objective parameters such as performance and pace, subjective factors such as the feeling of exertion also play a central role. The relationship between heart rate and performance provides valuable information on the training load, but must always be considered in combination with individual perception.