**3. Results**

#### *3.1. Characteristics of the Studied Groups*

The characteristics of the studied groups are given in Table 2.

In the police academy, the research included students of the police service preparation course. The group of people trained in the police prevention department was the youngest, which resulted from the student selection criteria, while students at the police school were characterizedbythehighestbodyweight.

#### *3.2. Energy Expenditure of Police Academy Students*

The study of students' energy expenditure was carried out during the implementation of tasks in the study program at the police academy. It included measurements both during typical theoretical classes and in field conditions, during which students learned how to use weapons, arrest procedures, chase, etc. The results of the energy expenditure of police officers carrying out typical training tasks during 8 h of training are presented in Table 3.


**Table 2.** Characteristics of police officers.

 Statistically significant difference at *p* < 0.05. IQR—interquartile range.

**Table 3.** Average energy expenditure of men studying in the police academy during an 8-h training day.


IQR—interquartile range.

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Analysis of the obtained results showed that the average energy load of police officers carrying out training tasks at the basic course in the police academy amounted to 2233 ± 546 kcal/8 h and varied depending on the activities performed. This value, according to Lehman's classification of workload, allows to classify the work performed as very heavy work [6].

#### *3.3. Energy Expenditure of Students at the Police Training Center*

3.3.1. Energy Expenditure of Students Trained on Specialist Courses for Police Officers

The research on energy expenditure covered 74 men, all students at the police training center trained on specialist courses for police officers intervening against aggressive and dangerous people and for instructors of police shooting in anti-terrorist police units. The mean body weight and mean height of the officers were 90.4 ± 13.8 kg and 179.7 ± 7.8 cm, respectively. The energy expenditure of police officers trained for the above-mentioned specialist courses included both training tasks of a theoretical nature (lectures) and those related to high physical activity, e.g., preparation and implementation of shooting. The results of the energy load of officers in relation to the training process are summarized in Table 4.

It was shown that the average energy expenditure of an officer associated with a typical 8-h day of program training was 2458 ± 723 kcal, which places the work performed in the category of very heavy work. It should be emphasized that there is a large variation in the results of energy load related to the implementation of various types of training. Theoretical training resulted in a low energy load of students, amounting to 1.75 kcal/min, which was characteristic of light work, while during intensive tactical classes, it amounted to 7.67 kcal/min, indicating the performance of hard work.


**Table 4.** Energy burden related to implementation of training at specialist courses at the police training center.

IQR—interquartile range.

3.3.2. Energy Expenditure of Officers Trained as Future Service Dog Handlers

Another assessment concerned the energy expenditure of officers trained as future service dog handlers. The study involved 18 officers, aged 34 ± 4.3 years, of an average body weight of 83.2 ± 16.0 kg and body height of 174.0 ± 7.0 cm. The training included training of patrol dogs and dogs for special tasks such as searching for drugs or explosives. The results of the energy expenditure of service dog handlers are summarized in Table 5.

**Table 5.** Energy load related to the training of officers—future service dog handlers.


IQR—interquartile range.

The energy expenditure related to the training of service dog handlers amounted to 2111 ± 834 kcal/8 h, which puts the severity of work performed in the category of very heavy work.

3.3.3. Energy Expenditure of Police Officers Who Perform Tasks on Waters

The police training center trains, among others, police officers who perform tasks on waters and in surrounding areas. During these courses, students acquire skills related to performing specialized tasks in the preventive service on water; rescuing and searching for people, property, and floating equipment; and maneuvering a boat in difficult and extreme weather conditions. They also acquire skills in organizing rescue operations, handling specialized rescue and navigation equipment, and learning to use modern means of transport, including water scooters, while on patrol. The training process takes place mainly on water and concerns driving and operating motorboats and navigation and rescue operations in water areas.

The study of energy expenditure of police officers connected with the specificity of this training covered 21 male officers, aged 34.5 ± 6.6 years, with an average body weight of 89.5 ± 10.9 kg and height of 184.5 ± 4.5 cm. The values of energy load associated with the training are summarized in Table 6.


**Table 6.** Energy burden of officers related to the training of policemen performing tasks on water.

IQR—interquartile range.

It was shown that an 8-h day of training resulted in an energy load of 1973 ± 553 kcal, indicating that they were performing heavy work. The relatively low energy expenditure of the water police trainees compared to those participating in other courses results from the specificity of patrolling water areas on motorboats, which is related to their low physical activity. Analysis of the average values of energy expenditure incurred by officers during the 8-h training process in the three centers included in the police training center showed that officers were burdened with different levels of energy expenditure, which resulted from the specificity of the training. The highest value of energy load related to the 8-h training day was found in officers trained on specialist courses and during the training of service dog handlers, which qualified the work as very hard work, while officers trained on water performed heavy work.

#### *3.4. Energy Expenditure of Policemen Trained in the Police School*

The police school specializes in training prevention police officers, i.e., those whose service has a direct impact on public order and the sense of security of citizens. Among other things, the school provides basic vocational training that every police officer admitted to the service must undergo. It prepares them for the implementation of tasks in basic executive positions (e.g., in patrol and intervention services, in police prevention units, or in a convoy service). Students gain knowledge and skills in the fields of law, crime prevention, forensics, intervention tactics and techniques, psychology, social communication, ethics, human rights, first aid, shooting training, and operation of IT and communication equipment. They learn how to perform patrol intervention and convoy protection services as well as the specifics of work as a district policeman and unit officer on duty.

A total of 47 male officers with an average body weight and height of 93.8 ± 15.3 kg and 180.4 ± 6.9 cm, respectively, were included in this energy expenditure study.

The results of the research on the energy load of officers during the 8-h training day are summarized in Table 7.

The results of the research on the energy expenditure of officers trained in the police school show that the work performed during the training is very hard work.

#### *3.5. Energy Expenditure of Policemen Trained in the Police Prevention Unit*

Police prevention units are designed mainly for team activities within compact subunits. The main tasks of these units include the following:


The study involved 60 officers with an average body weight of 83.7 ± 12.5 kg and an average body height of 180.3 ± 6.5 cm. The research included activities carried out on a typical training day, including combat tactics, drills, and shooting. Theobtainedresultsaresummarizedin Table8.

**N = 47 Training of Policemen at the Police School X** ± **SD Median Min Max IQR** Energy expenditure Time (h) 7.0 ± 2.70 6.5 2.5 24.0 1.5 kcal/h 283.0 ± 118.0 292.0 54.0 552.0 166.6 kcal/min 4.71 ± 1.96 4.86 0.90 9.20 2.8 kcal/h/kg bw 3.0 ± 1.2 2.8 0.7 5.7 2.0 kcal/min/kg bw 0.050 ± 0.020 0.047 0.011 0.095 0 kcal measured 1976.0 ± 947.0 1982.0 345.0 4930.0 1248 Pulse/min Maximum 159.6 ± 27.8 155.0 115.0 224.0 28 Minimum 66.2 ± 11.2 66.0 27.0 83.0 16 Average 92.9 ± 11.4 93.0 66.0 116.0 16 **Average kcal/8 h 2267** *±* **942 2334 936 4415 1332.6**

**Table 7.** Energy expenditure of male officers trained at the police school.

IQR—interquartile range.

**Table 8.** Energy expenditure of officers trained in the police prevention unit.


IQR—interquartile range.

It should be noted that in all examined police units, there was a large variation in the results, from low values of 1463.0 ± 339.0 kcal/8 h in the case of women's training up to high values of 3043 kcal/8 h, which was connected with the specificity, conditions, and nature of the training and service performed. The average values of energy expenditure of the police officers trained for 8 h in all divisions are summarized in Table 9.

The analysis of the obtained values of energy load of the examined students in relation to the training processes showed that their energy expenditure from the implementation of individual training tasks was similar and ranged from 0.42 to 0.71 kcal/min/kg bw (Table 10). Although the largest energy expenditure related to the implementation of individual training activities, as well as that related to the 8-h training process, was observed in the students of police prevention units, it was not a statistically significant difference. On the other hand, the lowest energy expenditure related to the training was observed in the water police.


**Table 9.** Average values of energy expenditure of the police officers trained within 8 h.

IQR—interquartile range.

**Table 10.** Differences in the value of energy expenditure related to the process and specificity of training students at police schools and training centers.


 Statistically significant difference at *p* < 0.05.

## **4. Discussion**

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Poland is one of the few countries where determination of the energy expenditure of workers on tasks at work is required by law. Information on how physically demanding work is (a measure of energy expenditure) at each workstation is essential not only for comparison with applicable regulations concerning maximum allowable values for regular work activity but also for work planning and taking proactive action to reduce the adverse health effects of work.

The value of energy expenditure related to an 8-h work shift should be taken into account when planning work, planning breaks, and allocating preventive meals and drinks by the employer. Heavy workload increases the risk of musculoskeletal system dysfunction, which is one of the causes of accelerated degenerative changes (especially of the spine) and an accelerated decline in exercise capacity. Hard physical work should also be considered a risk factor for cardiovascular disorders such as high blood pressure and ischemic heart disease. The assessment of energy expenditure, and thus the severity of work performed, allows to quantify the physical load of an employee according to his/her endurance capabilities.

Law enforcement is a highly stressful occupation that is prone to increasing the prevalence and incidence of cardiovascular disease. Evidence indicates that the prevalence of traditional cardiovascular risk factors among police officers is high (often higher than in the general population). Police work creates exposure to risk factors for the development of cardiovascular disease and diabetes and results in increased mortality rates [15–17]. Epidemiological studies sugges<sup>t</sup> that police officers and related public security personnel develop an increased risk of cardiovascular morbidity and mortality. Currently employed police personnel have a high prevalence of traditional risk factors, including hypertension, hyperlipidemia, metabolic syndrome, smoking, and a sedentary lifestyle. Moreover, low physical activity of policemen leads to a positive energy balance and, consequently, to

obesity [18,19]. Obesity may be more common among police officers compared with civilians, whereas diabetes is present less frequently. Law enforcement personnel are also exposed to occupational risk factors such as sudden physical exertion, acute and chronic psychological stress, shift work, and noise [16]. Obesity not only affects the ability of police officers to perform their work-related duties, but consequently, it may also impact public safety.

In the available literature, there are few works concerning the energy expenditure of students at police schools and police officers trained in police training centers. The values of energy expenditure obtained in the present study indicate that the energy loads of students and trainees participating in training programs in Polish police schools and police training centers range from 1973 ± 553 to 3043 ± 1308 kcal/8 h of work. These values place their work in the category of very hard work.

Studies in police schools can be compared to studies from fire service schools. The results of earlier research revealed that the values of energy expenditure during typical activities from the training program prepared for students at the Main School of Fire Service were diverse and ranged from 1.49 to 10.66 kcal/min. According to Christensen's classification of work severity, the work performed by students can be classified as light work to very heavy work [20]. The average daily energy load of students at the Main School of Fire Service on a typical day of training on the training ground was 4745 ± 1181 kcal/d, which means that the work performed should be considered, according to the obligatory classification of work intensity, as very heavy [11].

Previous studies on the energy load of students at the National Fire Service Aspirants School showed that their daily energy expenditure from the training process amounted to 3735.5 kcal, while during 8 h of program classes, students expended only 1289.5 kcal [12].

Historical studies on the energy burden of 30 male and 10 female police cadets, randomly selected from the Singapore Police Force, showed that the value of daily energy expenditure associated with duty and training tasks was 3028 and 1752 kcal, respectively [21].

A study on the energy expenditure of 28 healthy police officers working in shifts showed that the energy expenditure was 3062 kcal/d during night shifts, amounted to 2647 kcal/d during day shifts, and was the lowest on holiday duty, when it amounted to 2310 kcal/d [22].

An assessment of the service-related daily energy expenditure of Malaysian police officers showed that males expended 2639.6 ± 229.4 kcal/d and females 2268.9 ± 203.5 kcal/d [23].

The values obtained in the present study on energy expenditure associated with studies and training in Polish police schools and police training centers confirm the results of previous research, indicating that both studies and police training as well as police service are characterized by work that falls into the category of heavy work.
