RU2722265C2 - Method of determining physical performance - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine and cardiology, particularly to sports medicine, physiotherapy exercises and medical functional diagnostics, and can be used to control a person's physical performance. Dynamic weight of a person is measured during two consecutive loads. After each exercise heart rate is measured. During exercise, body weight P is measured by sensors. Digital signal from the weights is transmitted to a computer, where mechanical work is calculated by double numerical integration of the measurement results, calculating the average power and the value of the index of physical working capacity.EFFECT: method enables determining physical performance in untrained adults and patients suffering a cardiovascular pathology, unifying evaluation of physical performance determination results and taking into account energy costs, as well as improving accuracy of determining physical performance.5 cl, 3 tbl, 5 ex

Description

The invention relates to the field of medicine and cardiology, in particular, to sports medicine, physiotherapy exercises and medical functional diagnostics, and can be used to control a person’s physical performance and his tolerance to physical activity, as well as to assess the physical performance of both healthy and sick people and for modeling the measured load of the athlete.

State of the art

Currently, various methods for determining the physical performance of a person are known. In medical practice, tests with dosed physical activity have found their application, namely, a test using bicycle ergometry, a test using treadmill (Amosov N.M., Bendet Y.A. Physical activity and heart. - 2nd ed., Revised. And add.- K .: Zdorov'ya, 1984. - S. 56-64 .; Aronov D.M., Lupanov V.P. Functional tests in cardiology. - M: MEDpress-inform, 2003. - 2nd ed. . - pp. 21-26.)

During bicycle ergometry, the test subject performs physical activity (pedals) at the pace set by the operator. After 2-3 minutes of successful completion, the load increases. A stepwise increasing load is used (the load value is expressed in watts). The test is terminated when the criteria for termination of the load.

The disadvantages of bicycle ergometry are: a feeling of inconvenience from prolonged sitting in the saddle, the appearance of fatigue and pain in the quadriceps muscles, which bear the main burden, the occurrence of an anginal attack, life-threatening arrhythmias, headache, nausea, vomiting with inadequate loads, which requires the location of the room, in which bicycle ergometry is performed, in close proximity to the intensive care unit, or the diagnostic room must be fully equipped for the autonomous performance of full-fledged resuscitation measures, and the study must be carried out in the presence of a specialist doctor for functional diagnostics and a nurse.

The treadmill test is a run on a moving track with a certain speed and a certain angle of incline. Constant phased, every 1 or 3 minutes, increasing physical activity, due to the increase in speed and tilt of the track, is performed until the criteria for termination of the load.

The disadvantages of the test using treadmill are: the high cost of the treadmill, their bulkiness, and physical performance indicators are measured in miles per hour, which is difficult to compare with the watts that are usual for doctors, in addition, the load on the treadmill is largely determined by the mass of the subject, which makes comparison difficult results in continuous dynamics.

Known methods for assessing the physical performance of a person using the simplest forms of performing physical activity that do not require special equipment (Belotserkovsky ZB, Lyubina BG, “Cardiac activity and functional fitness of athletes (normal and atypical changes in normal and altered adaptation conditions physical activity) / Z. B. Belotserkovsky, B. G. Lyubina [Text].-M .: Soviet Sport, 2012.-P. 91-101.) These include:

a) test with running in place (Kotov-Deshin test), which consists in assessing the adaptation of the cardiovascular system to stresses aimed at developing endurance (2-3 minutes running with high lifting of the thigh (at the top of the thigh parallel to the floor) at a speed of 180 steps per minute). Evaluation of the sample is carried out according to the type of reaction of the cardiovascular system and recovery time;

b) Ruthier’s test (Restorative medicine: a textbook / edited by V. A. Epifanov. - M.: GEOTAR-Media, 2012. - p. 72), which consists in determining the functional reserve of the cardiovascular system, based on the value of the pulse, fixed at various stages of recovery after a relatively small load (15 squats for 45 seconds);

c) a test with climbing stairs (Harvard step test), which consists in assessing a person’s physical performance based on the value of the pulse recorded at various stages of recovery after climbing a step of a certain height with a frequency of 30 per minute for 5 minutes.

Evaluation of performance by the above methods either allows you to get only a general indicative picture of the functional state of a person or may be applicable to people with sufficient physical fitness, and not to persons of older and older age, since it can cause significant functional changes.

A known method of assessing exercise tolerance and objectification of the functional status of patients with heart and lung diseases (Lipkin DP, Scriven AJ, Crake T., Poole-Wilson PA Six minute walking test for assessing exercise capacity in chronicheart failure. British Medical Journal 1986; 292 : 653-655 .; Manual on outpatient cardiology / under the editorship of Yu.N. Belenkov, RG Oganova. - M .: GEOTAR-Media, 2007. - S. 66-68.) - test 6- minute walk, consisting in the fact that when conducting a 6-minute step test, the patient is tasked to walk the greatest possible distance in 6 minutes (according to the measured [30 m] and marked out through 1 m corridor at your own pace), after which the distance is recorded . Before and at the end of the test, dyspnea is assessed according to the Borg scale, pulse, and, if possible, oxygen saturation (in the presence of a pulse oximeter). The distance covered within 6 minutes is measured in meters and compared with the proper indicator. Proper indicators are calculated using formulas that take into account age in years, body weight in kilograms, height in centimeters, and body mass index. Based on the distance traveled, a conclusion is made about the functional status of the patient (the functional class of heart failure).

The disadvantage of this method is the low accuracy of determining the test results: 1) the 6-minute walk test is highly sensitive to changes in its methodology, therefore it is recommended that the technical requirements for its reproduction be clearly observed; 2) when performing a 6-minute walk test, the relationship between the maximum oxygen consumption (max Vo ₂ ) and the distance traveled during the test is non-linear; 3) the 6-minute walk test is intended for the diagnosis of patients with severe chronic heart failure (according to NYHA - CHF 2 functional class (fc) and 3 fc), but is not suitable for assessing the health status of patients with mild chronic heart failure insufficiency (CHF) (according to NYHA - CHF 1st functional class); 4) an estimated indicator with which the distance traveled by a specific individual is compared, calculated using coefficients selected empirically; 5) the results of a test with a 6-minute walk are determined by subjective factors, the main of which is the nature of the patient’s motivation, while the patient can significantly slow down his arbitrary walking speed, due to his subjective motivation, and not realize the important condition for the test - walk possible faster in 6 minutes.

The prototype of the proposed method for determining physical performance is a test S.P. Letunova (Belotserkovsky ZB, Lyubina B.G. Cardiac activity and functional preparedness in athletes (normal and atypical changes in normal and altered conditions of adaptation to physical activity) / Z. B. Belotserkovsky, B.G. Lyubina [Text] . - M .: Soviet Sport, 2012. - pp. 94-98.), More precisely, the 1st component of this three-component test. The test consists of three loads: the first - 20 squats performed in 30 seconds, the second - a 15-second run in place at the maximum pace, and the third - three-minute run in place at a pace of 180 steps in 1 minute.

The test is used in sports and medical research, and is intended to determine the nature of the body’s adaptation to high-speed work and “endurance” work according to the characteristics of the recovery period. This functional test is simple, affordable, quite informative, and is the most popular method for determining physical performance in physical culture and sports. . The disadvantage of this sample is the low accuracy of determining the results: assessment of the results of the sample S.P. Letunova is not quantitative, but qualitative. It is conducted by studying the so-called types of reactions: normotonic type; atypical types - hypertonic, hypotonic, dystonic and a reaction with a stepwise increase in maximum blood pressure. This functional test does not allow to evaluate physical performance (PWC ₁₇₀ ), which is by far the most recognized criterion for the state of physical performance of a person. This is due to the fact that in the sample S.P. Letunova there is no possibility of calculating the power of the load performed.

The disadvantages of the known methods eliminates the claimed technical solution.

An object of the invention is the unification of the assessment of the results of determining physical performance, accounting for energy costs, as well as improving the accuracy of determining physical performance.

The method for determining physical performance by changing the heart rate after performing deep squats includes the following steps: 1) determining the patient’s sitting position before measuring the initial level of blood pressure (blood pressure) and heart rate (heart rate); 2) assigning the patient a physical load, including the first load of 10 squats in 30 seconds and the second load of 20 squats in 30 seconds, and during the squat at the first and second loads, the arms should be stretched forward, and when straightening the legs down, directly into At the end of each load, the heart rate is recorded, then during the first 40 seconds of the first minute after the load, blood pressure is measured.

The patient performs the exercise at the first and second loads, standing on an electronic scale. During the exercise, body weight P is measured by sensors. A digital signal from the balance enters a computer, where the power of the performed loads and the level of physical performance are determined by calculation. At the input of the computer receives an array of values of weight P _i counted with an interval of 0.005 s. while doing loads.

The acceleration of the patient’s center of mass at any time during the squat is determined using the laws of dynamics through the ratio of dynamic and static weights; the center of mass velocity is calculated by numerically integrating the acceleration over time. The array of speed values is subjected to a second integration over time, as a result of which there is a vertical displacement of the center of mass during the climb from the squat. From the calculated values of the vertical displacement of the center of mass, perfect work is calculated. Power W is found as the ratio of work to the time the exercise is performed.

The obtained heart rate values at the end of the first and second loads and the calculated power values of the first and second loads are placed in a modified version of the Physical Working Capacity formula for the PWC170 test - a formula for determining physical performance in people engaged in mass physical culture (PWC _AF test - physical performance with heart rate (F-frequency) changing with age (A - age).

The value of PWC170 is calculated using the standard formula

where W ₁ and W ₂ are the power of the first and second loads, respectively, ƒ ₁ and ƒ ₂ are the heart rate after these loads.

The PWC _AF value is calculated by the formula

where W ₁ and W ₂ are the power of the first and second loads, respectively, ƒ ₁ and ƒ ₂ are the heart rate after these loads, F is the heart rate of approximately 87% (0.87 × (220 is the age)) of the maximum age pulse.

The standard test PWC170 involves performing two exercises (loads) for 5 minutes each with a 3-minute rest interval between them; while the load power is set so that the heart rate at the end of the first and second exercises is 110-120 beats / min and 145-160 beats / min, respectively (Belotserkovsky Z.B., Lyubina B.G. Cardiac activity and functional fitness of athletes (norm and atypical changes in normal and altered conditions of adaptation to physical activity) / Z. B. Belotserkovsky, B. G. Lyubina [Text]. - M.: Soviet Sport, 2012. - S. 104-107.). The indicated time for performing the exercises and their intensity are obviously unacceptable for patients suffering from certain cardiovascular diseases.

For these reasons, a lightweight test version is proposed that uses a method of setting physical activity that maintains a high correlation with the traditional one, which uses a bicycle ergometer, and also retains the ability to evaluate the body's response to physical activity, supplemented by the ability to quantify the power of physical exercise performed, with subsequent calculation PWC ₁₇₀ (PWC _AF ). In the inventive method, in contrast to the prototype, the load lasts 30 seconds, and the traditional exercise on the bicycle ergometer is replaced by a series of squats. An essential regularity underlying the PWC170 test is the linear relationship between exercise power and heart rate. From these considerations, an experimental check was made of the presence of a linear connection with lesser loads and a shorter exercise time. The experiment was carried out on a sample of 25 people, each of whom performed three series of squats in the amount of 10, 15 and 20 in 30 seconds. The average measurement results are given in table. 1, 2, where the measured heart rate (HR) is reflected depending on the load power W.

From the test results (see table. 1, 2) it is seen that the linear relationship between the load power and the heart rate in the present method is observed with high accuracy. This circumstance justifies the use of a lightweight version of the PWC170 test to measure the physical performance index of elderly and sick people.

Since the proposed lightweight test methodology in terms of the nature of the load and the time it takes to complete the exercises differs from the standard method using a bicycle ergometer, the PWC _AF obtained by the proposed method is slightly different from the standard one.

To bring the values to comparable generally accepted in the formula for calculating PWC _{AF, a} correction empirical coefficient k is introduced, which is found as the ratio of the PWC _AF value (PWC170) obtained by the standard method to the value obtained by the claimed method. Correction empirical coefficient k = 0.25 ± 0.03.

The technical result of the invention is the unification of the assessment of the results of determining physical performance and accounting for energy costs, as well as improving the accuracy of determining physical performance.

The technical result is achieved by a method of determining physical performance, including assigning the patient a physical load consisting of squats with measuring heart rate and blood pressure, characterized in that the squat is performed on a balance with the ability to transfer weight data, the first load consists of 10 squats in 30 seconds, the second load of 20 squats per 30 seconds, and during the squat at the first and second loads, the arms should be extended forward, and when straightening the legs down;

they monitor the blood pressure and heart rate of the patient in a sitting position before the load, then, in order to dynamically monitor the patient’s condition, immediately at the end of each load, the pulse rate is recorded, then blood pressure is measured during the first 40 seconds of the first minute after the load;

in the process of performing exercises by a person, standing on electronic scales, an array of values of a person’s body weight, counted at intervals of not more than 0.005 s, is transmitted to a computer, it is processed by calculating the amount, the value of which is used to calculate mechanical work, the indicator of which is used to calculate the average power performed load

then calculate the power of physical work (PWC _AF ) according to the modified, with the introduction of an empirical correction coefficient k according to the formula:

where W ₁ and W ₂ - power respectively of the first and second loads,

ƒ ₁ and ƒ ₂ - heart rate after these loads,

F - heart rate component of 0.87 × (220 - age);

k is a correction, empirical coefficient equal to 0.25,

the resulting PWC _AF value determines the physical performance according to table 3 contained in the description.

As an option, when determining the initial level of heart rate in a sitting position, the pulse rate is calculated by palpation for ten-second time intervals, or by electrocardiographic method.

Another option, in which the rhythm of the first and second loads is set by a metronome or imitation of a metronome in an electronic device.

The technical solution is explained in tables 1, 2, 3.

Tab. 1. The dependence of the power and heart rate from the load.

Tab. 2. A table of the linear dependence of the power of the work performed (abscissa) on heart rate (ordinate).

Tab. 3. Assessment of physical performance in people of different sex and age according to the PWCAF test with the modification: kgm / min converted to watts. (Belotserkovsky Z. B., Lyubina B. G. Cardiac activity and functional preparedness in athletes (normal and atypical changes in normal and altered conditions of adaptation to physical activity) / Z. B. Belotserkovsky, B. G. Lyubina [Text]. - M.: Soviet Sport, 2012 .-- S. 131-132.)

An example implementation.

The method for determining physical performance includes monitoring before measuring the initial level of blood pressure and heart rate of the subject in a sitting position, while the pulse rate is calculated until a stable result is obtained; assigning the patient a physical load, including the first load of 10 squats in 30 seconds and the second load of 20 squats in 30 seconds, and during the squat at the first and second loads, the arms should be stretched forward, and when straightening the legs down, directly at the end of each load, record the heart rate, then during the first 40 seconds of the first minute after the load, blood pressure is measured; in the process of performing exercises by a person, standing on electronic scales, an array of values of a person’s body weight, counted at intervals of 0.005 s, supplied to a computer, using the second Newton’s law, is converted into an array of values of the acceleration of the individual’s center of mass, then, through the numerical integration of time acceleration, Calculation of an array of velocities of the center of mass at certain points in time when squatting the array of speeds is then subjected to a second numerical integration to find the vertical displacement of the center of mass during the climb out of the squat, by calculating the amount, the value of which is used to calculate the mechanical work, the indicator of which is used to calculate the average power of the load, the numerical indicator of which is used to calculate the power of the physical work, expressed in deep squats at the appropriate pace, which, in turn, is used to determine the level of physical performance; calculation of the power of physical work, in which the heart rate reaches the indicator, the maximum permissible for the corresponding age, values for the modified, with the introduction of the empirical correction coefficient k according to the formula:

where W ₁ and W ₂ are the power of the first and second loads, respectively, ƒ ₁ and ƒ ₂ are the heart rate after these loads, F is the heart rate of 0.87 × (220 is the age) of the maximum age pulse; k is a correction, empirical coefficient, which is defined as the ratio of the physical performance determined using the standard PWC _AF test (PWC170), carried out according to the standard method using a two-stage load, and the physical performance value determined using the PWC _AF test (PWC170), calculated using the power of two loads obtained during the proposed method, correctional, empirical, coefficient k = 0.25 ± 0.03; the regularity underlying the standard PWC _AF test (PWC170), namely, the linear relationship between physical exercise power and heart rate, when carrying out the proposed method, is observed with high accuracy and is confirmed experimentally.

When determining the initial level of heart rate in a sitting position, the pulse rate is calculated either by palpation for ten second time intervals, or by electrocardiographic method. The rhythm of the first and second loads is set by a metronome or a metronome program in a PC / mobile device.

The method is illustrated by the following examples.

Using the method in healthy individuals.

Example No. 1.

Patient K., 21 years old, body weight 72 kg, height 179 cm, with a diagnosis: practically healthy.

When assessing performance by the claimed method, the subject consistently performed two loads - a series of 10 squats in 30 seconds (first load) and a series of 20 squats in 30 seconds (second load), with a 3-minute rest interval between them. At the end of each load, among other indicators, the value of the variable formula for calculating the desired PWC _{AF was} determined - the pulse was calculated (by palpation or electrocardiographic method). The heart rate at the end of the first load is 108 beats per minute. The heart rate at the end of the second load is 123 beats per minute. The power of the first load was 104 watts, the power of the second load was 200 watts.

The computer program implements the algorithm for calculating PWC _AF according to the standard formula. As a result of the calculation, PWC _AF = 521 W.

The next day, the PWC _AF test was carried out according to the standard method for bicycle ergometry. The patient consistently performed two loads for 5 minutes with a 3-minute rest interval between them, the power of the first load was 72 W, the power of the second load was 112 W. The heart rate at the end of the first load is 136 beats per minute. The heart rate at the end of the second load is 164 beats per minute. By extrapolation, PWC _AF = 125 W was calculated. The empirical correction factor was 0.24. The physical performance of the patient is below average. Table 3 (Belotserkovsky Z.B., Lyubina B.G. Cardiac activity and functional preparedness in athletes (normal and atypical changes in normal and altered conditions of adaptation to physical activity) / Z. B. Belotserkovsky, B.G. Lyubina [Text ]. - M.: Soviet Sport, 2012. - S. 131-132.).

Example No. 2.

Patient V., 35 years old, body weight 73 kg, height 175 cm, with a diagnosis: almost healthy.

When assessing performance by the claimed method, the subject consistently performed two loads - a series of 10 squats in 30 seconds (first load) and a series of 20 squats in 30 seconds (second load), with a 3-minute rest interval between them. At the end of each load, among other indicators, the value of the variable formula for calculating the desired PWC _{AF was} determined - the pulse was calculated (by palpation or electrocardiographic method). The heart rate at the end of the first load is 114 beats per minute. The heart rate at the end of the second load is 124 beats per minute. The power of the first load was 94 watts, the power of the second load was 232 watts.

The computer program implements the algorithm for calculating PWC _AF according to the standard formula. As a result of the calculation, PWC _AF = 742 W.

The next day, the PWC _AF test was carried out according to the standard method for bicycle ergometry. The patient consistently performed two loads for 5 minutes with a 3-minute rest interval between them, the power of the first load was 73 W, the power of the second load was 150 W. The heart rate at the end of the first load is 112 beats per minute. The heart rate at the end of the second load is 148 beats per minute. By extrapolation, PWC _AF = 178 W was calculated. The empirical correction factor was 0.24. The physical performance of the patient is above average.

Hypertensive patients

Example No. 3.

Patient M., 46 years old, body weight 84 kg, height 160 cm, with a diagnosis of Hypertension 1 degree.

When assessing performance by the claimed method, the subject consistently performed two loads - a series of 10 squats in 30 seconds (first load) and a series of 20 squats in 30 seconds (second load), with a 3-minute rest interval between them. At the end of each load, among other indicators, the value of the variable formula for calculating the desired PWC _{AF was} determined - the pulse was calculated (by palpation or electrocardiographic method). The heart rate at the end of the first load is 114 beats per minute. The heart rate at the end of the second load is 136 beats per minute. The power of the first load was 119 watts, the power of the second load was 227 watts. The computer program implements the algorithm for calculating PWC _AF according to the standard formula. As a result, PWC _AF = 302.5 watts.

The next day, the PWC _AF test was carried out according to the standard method for bicycle ergometry. The patient consistently performed two loads for 5 minutes with a 3-minute rest interval between them, the power of the first load was 42 W, the power of the second load was 61 W. The heart rate at the end of the first load is 124 beats per minute. The heart rate at the end of the second load is 140 beats per minute. By extrapolation, PWC _AF = 75 W was calculated. The empirical correction factor was 0.25. Physical performance in the patient is average.

Example No. 4.

Patient 3., 54 years old, body weight 76 kg, height 153 cm, with a diagnosis of Hypertension 1 degree.

When assessing performance by the claimed method, the subject consistently performed two loads - a series of 10 squats in 30 seconds (first load) and a series of 20 squats in 30 seconds (second load), with a 3-minute rest interval between them. At the end of each load, among other indicators, the value of the variable formula for calculating the desired PWC _{AF was} determined - the pulse was calculated (by palpation or electrocardiographic method). The heart rate at the end of the first load is 104 beats per minute. The heart rate at the end of the second load is 120 beats per minute. The power of the first load was 102 watts, the power of the second load was 197 watts.

The computer program implements the algorithm for calculating PWC _AF according to the standard formula. As a result of the calculation, PWC _AF = 342 watts.

The next day, the PWC _AF test was carried out according to the standard method for bicycle ergometry. The patient consistently performed two loads for 5 minutes with a 3-minute rest interval between them, the power of the first load was 38 watts, the power of the second load was 57 watts. The heart rate at the end of the first load is 116 beats per minute. The heart rate at the end of the second load is 132 beats per minute. By extrapolation, PWC _AF = 72 W was calculated. The empirical correction factor was 0.21. Physical performance in the patient is average.

Patient with past myocardial infarction

Example No. 5.

Patient B., 51 years old, body weight 72 kg, height 173 cm, with a diagnosis of Postinfarction cardiosclerosis (myocardial infarction suffered 3 years ago).

When assessing performance by the claimed method, the subject consistently performed two loads - a series of 10 squats in 30 seconds (first load) and a series of 20 squats in 30 seconds (second load), with a 3-minute rest interval between them. At the end of each load, among other indicators, the value of the variable formula for calculating the desired PWC _{AF was} determined - the pulse was calculated (by palpation or electrocardiographic method). The heart rate at the end of the first load is 114 beats per minute. The heart rate at the end of the second load is 126 beats per minute. The power of the first load was 91 watts, the power of the second load was 208 watts.

The computer program implements the algorithm for calculating PWC _AF according to the standard formula. As a result of the calculation, PWC _AF = 413 watts.

The next day, the PWC _AF test was carried out according to the standard method for bicycle ergometry. The patient consistently performed two loads for 5 minutes with a 3-minute rest interval between them, the power of the first load was 36 W, the power of the second load was 87 W. The heart rate at the end of the first load is 88 beats per minute. The heart rate at the end of the second load is 136 beats per minute. By extrapolation, PWC _AF = 99 W was calculated. The empirical correction factor was 0.24. The physical performance of the patient is above average.

Claims (14)

1. A method for determining physical performance, including assigning the patient a physical load consisting of squats with measurement of heart rate and blood pressure, characterized in that the squats are performed on a balance with the ability to transfer weight data, the first load consists of 10 squats for 30 s, the second load is 20 squats for 30 s, and during the squat at the first and second loads, the arms should be extended forward, and when straightening the legs down; they monitor the blood pressure and heart rate of the patient in a sitting position before the load, then immediately at the end of each load register the heart rate, then during the first 40 from the first minute after the load, blood pressure is measured; in the process of performing exercises by a person, standing on electronic scales, an array of values of a person’s body weight, counted at intervals of not more than 0.005 s, is transmitted to a computer, it is processed by calculating the amount, the value of which is used to calculate mechanical work, the indicator of which is used to calculate the average power performed load then calculate the power of physical work (PWC _AF ) according to the modified, with the introduction of an empirical correction coefficient k according to the formula:

where W ₁ and W ₁ - power respectively of the first and second loads, ƒ ₁ and ƒ ₂ - heart rate after these loads, F - heart rate component of 0.87 × (220 - age); k is a correction empirical coefficient equal to 0.25, the resulting PWC _AF value determines the physical performance according to table 3 contained in the description. 2. The method for determining physical performance according to claim 1, characterized in that when determining the initial level of heart rate in a sitting position, the pulse rate is calculated by palpation for ten second time intervals. 3. The method for determining physical performance according to claim 1, characterized in that when determining the initial level of heart rate in a sitting position, the pulse rate is calculated by the electrocardiographic method. 4. The method for determining physical performance according to claim 1, characterized in that the rhythm of the first and second loads is set by the metronome. 5. The method for determining physical performance according to claim 1, characterized in that the rhythm of the first and second loads is set by imitating a metronome in an electronic device.

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