Method of defining the physical condition level of a person, said method comprising: - employing a measuring device to perform, during a plurality of training sessions, parallel measuring of the heart rate and of the performance of the person, as well as measuring of other parameters influencing the physical performance of the person, said other parameters being parameters of the environment in which the physical performances are carried out and parameters characterizing the health condition of the person evaluated, - transmitting the measured values to an evaluation device, - creating, by the evaluation device, a database containing records, each record containing a set of pairs of heart rate values and performance values of the person measured during a training session and arranged chronologically, as well as information on the date of measuring and on the other parameters influencing the physical performance of the person, - processing, by the evaluation device, the database records, so that, for each record, first performance values that have identical value of the heart rate assigned are grouped, and then arithmetic means are defined from these performance values, resulting in a set of data pairs representing that specific record from the database and containing information on the heart rate and its corresponding average performance, and subsequently filtration of the data pair sets is carried out, so that at least two data pair sets that have the same parameters influencing the physical performance are filtered out and displayed in a diagram, wherein the x-coordinate contains the heart rate value and the y-coordinate contains its corresponding average performance value, and - using the curves defined by the displayed data pairs sets for evaluating the physical condition level of the person during the at least two training sessions, whereby higher average performance values for the same heart rate values indicates a higher physical condition level, the method further comprises the step of, - selecting one of the data pair sets so as to define its average performance values as zero and determine the difference between the average performance values of the other data pair sets and those of the selected data pair set for each heart rate, so that a further set of pairs is created containing the heart rate values and values of differences in individual average performances of the records compared so as to assess the development of physical condition level of the person, wherein the difference in the individual average values at a given pulse rate between two compared records is included in the weighted arithmetic mean as the sum of the frequency of the sets of performance pairs and the specific heart rate is included in both records compared. - employing a measuring device to perform, during a plurality of training sessions, parallel measuring of the heart rate and of the performance of the person, as well as measuring of other parameters influencing the physical performance of the person, said other parameters being parameters of the environment in which the physical performances are carried out and parameters characterizing the health condition of the person evaluated, - transmitting the measured values to an evaluation device, - creating, by the evaluation device, a database containing records, each record containing a set of pairs of heart rate values and performance values of the person measured during a training session and arranged chronologically, as well as information on the date of measuring and on the other parameters influencing the physical performance of the person, - processing, by the evaluation device, the database records, so that, for each record, first performance values that have identical value of the heart rate assigned are grouped, and then arithmetic means are defined from these performance values, resulting in a set of data pairs representing that specific record from the database and containing information on the heart rate and its corresponding average performance, and subsequently filtration of the data pair sets is carried out, so that at least two data pair sets that have the same parameters influencing the physical performance are filtered out and displayed in a diagram, wherein the x-coordinate contains the heart rate value and the y-coordinate contains its corresponding average performance value, and - using the curves defined by the displayed data pairs sets for evaluating the physical condition level of the person during the at least two training sessions, whereby higher average performance values for the same heart rate values indicates a higher physical condition level, the method further comprises the step of, - selecting one of the data pair sets so as to define its average performance values as zero and determine the difference between the average performance values of the other data pair sets and those of the selected data pair set for each heart rate, so that a further set of pairs is created containing the heart rate values and values of differences in individual average performances of the records compared so as to assess the development of physical condition level of the person, wherein the difference in the individual average values at a given pulse rate between two compared records is included in the weighted arithmetic mean as the sum of the frequency of the sets of performance pairs and the specific heart rate is included in both records compared.