1. Introduction
Due to recent events in Spain, where inadequately trained police officers face approximately 35 attacks per day [
1], concerns have arisen in various media outlets regarding the level of self-defense training provided to law enforcement. The training for both public and private security forces is deemed inadequate or deficient. The circumstances for security forces in Spain can be likened to those of a surgeon who has received minimal training of just 70 hours and is expected to operate on patients without additional practice.
A study by Strömmer et al. [
2] provides evidence that over time, law enforcement forces in the United States are causing more frequent and serious injuries to civilians. Taking a macro approach to programs, research studies conducted by Staller et al. [
3] suggest pitfalls in the design of training objectives and the actual program, leading to a lack of alignment between training outcomes and the expected performance of novice police officers in the field.
Concerning European law enforcement agencies, they operate in various contexts, and their access to resources for management or training delivery is variable. Despite differences in contexts and resources, these agencies face common training challenges, such as time-consuming organizational and administrative processes required to implement changes in current training practices [
4,
5].
Numerous debates surround the professionalization and reform of the police, a discourse that has intensified since the death of George Floyd [
6]. This heightened discussion underscores the need for a deeper understanding of the scientific methods employed in police education and training [
7].
Recent research substantiates the reservations expressed in this study regarding the efficacy of police training and advocates for a more realistic approach to real-world violence [
8].
Police officers on patrol encounter diverse and challenging contexts from mental, social, and physical perspectives, which can impact their overall well-being [
8,
9,
10]. Recognizing these challenges, Vera-Jiménez [
11] initiated a local-scale study in Cádiz, a town in southern Spain with a population slightly exceeding 100,000 inhabitants. The study aimed to provide specific training based on Operational Tactical Procedures (OTP) [
12,
13] to a group of municipal police officers.
The outcomes of the study indicate that the implementation of OTP procedures led to a substantial reduction in sick leave among officers during the training period and for a certain duration following the completion of the training, in comparison to periods when no OTP education was provided. This positive impact stands in contrast to conventional police training methods, currently endorsed and rooted in military instruction, martial arts, and other forms of fight and combat sports (MA/F/CS). OTP procedures were specifically developed as an alternative to classical police training [
14], driven by two primary considerations: a) the potential harm inflicted on citizens subjected to Physical Intervention Techniques (PITs) [
11,
15], and b) the heightened risk of injury to police officers executing such PITs [
13,
16].
The findings underscore the effectiveness of OTP procedures in minimizing sick leaves among police officers, emphasizing a departure from traditional training approaches to enhance both citizen safety and officer well-being.
In Vera-Jiménez's study [
11], an anatomical map was already devised to delineate areas on the human body of citizens for which Physical Intervention Techniques (PITs) were either recommended or prohibited. This mapping resulted from an examination of a series of judicial sentences issued by the Supreme Court, which had consequences for police officers employing force through conventional PITs [
15].
Wearable sensor systems utilizing inertial measurement units (IMUs) provide kinematic information [
17], proving especially valuable in ergonomic evaluations designed to capture data associated with high-risk postures and flexion frequency. These IMU systems are presently under exploration and adoption in the industry to complement or expedite ergonomic assessments [
18]. While industry reports underscore the utility of IMU systems in identifying and mitigating risks of musculoskeletal injuries, manufacturers of these devices currently assert quantitative claims about the effectiveness and capabilities of their IMU systems in injury reduction. However, a dearth of formal, independent, or peer-reviewed studies exists to evaluate these IMU systems or the scientific foundation underpinning their risk assessment algorithms.
The processed data, acquired using the "Biomechanics of Bodies" (BoB) [
19] analysis software, were subjected to a comparison with values corresponding to the newly defined Tactical Operating Procedures. This comparison relied on the REBA [
20] and Marras [
21] methods. BoB encompasses an extensive array of biomechanical functionalities, incorporating modeling capabilities to handle parameters such as position, velocity, acceleration (both linear extensions and angular muscle rotations), muscle tension, compressive force, and energy or power data. Additionally, BoB is equipped to generate three-dimensional graphic representations and provides various modes for data visualization.
To ascertain potential injuries that police officers may face, a suit equipped with sensors for capturing motion and other variables (Rokoko Smartsuit Pro) served as a fundamental instrument for this study. This equipment yielded a dataset that could be analyzed using Biomechanics of Bodies (BoB) software applications [
19], which efficiently manages results, enabling the assessment of risks through the REBA and Marras Probability of High Risk methods.
The first method is a widely employed ergonomic tool designed to analyze and assess the ergonomic aspects of work tasks with the aim of identifying and preventing ergonomic risks in the workplace. REBA is particularly utilized in industries characterized by repetitive or physically demanding tasks, such as manufacturing, construction, or healthcare. This methodology involves a healthcare professional or ergonomist observing a worker during a specific task. The assessment takes into account factors such as body posture, required force, repetition, task duration, and exposure to vibrations. Individual scores are assigned to each of these factors, contributing to an overall ergonomic risk score. This cumulative score serves as a guide for implementing targeted improvements, which may include adjustments to operating procedures or the adoption of safer equipment. The primary objective of REBA is to mitigate ergonomic hazards, promoting a safer and healthier work environment to prevent injuries and safeguard the well-being of workers [
20].
The prevalence of musculoskeletal diseases is substantial, affecting approximately 1.71 billion people globally, as estimated by the World Health Organization (WHO) [
22]. These conditions constitute a significant global cause of disability, with low back pain emerging as the predominant factor in 160 countries [
22]. Moreover, the annual global burden of work-related high blood pressure is estimated to be approximately 22 million disability-adjusted life years [
23].
When considering the costs associated with occupational accidents and illnesses, musculoskeletal disorders (MSDs) constitute approximately 40% of the total [
24]. The economic and social impact of these disruptions is reflected in estimates that place the costs at 3.9% of the global gross domestic product and 3.3% of the gross domestic product in the European Union [
25].
Clearly, work-related illnesses and disorders impose an economic burden on both companies and societies at large, simultaneously affecting the individual well-being of people. This analysis differentiates between high and low risks of occupationally-related low back disorders, employing a classification system rooted in a multiple logistic regression model. This model comprises a combination of five trunk motions and workplace factors to determine the likelihood of such disorders [
21,
26,
27].
This study specifically addresses the application of the aforementioned methods to analyze the outcomes of training novice police officers in the application of Use of Force (UOF) based on OTP basic technique 1. Our research is focused on assessing the risk of injuries associated with UOF, emphasizing the implications of the training outcomes.
The training received in the use of police force, specifically in basic technique 1 of Operational Tactical Procedures (OTP) (Figure 4), used in arrest procedures to control a standing person, was evaluated using police ergonomics parameters (PEP), as described in a previous work by Vera et al [
12]. These parameters, in conjunction with Marras, were applied to a cohort of four (4) novice police officers, seven (7) with average experience, and one (1) expert. These individuals volunteered from the School of Public Safety of the City of Cádiz. The training on Tactical Operational Procedures from the Prosecutor's Office lasted 30 hours for new police officers, 80 hours for those with average experience, and 200 hours for the expert [
12].
Author Contributions
Conceptualization, J.C.V.-J. (José C. Vera-Jiménez) and J.A.; acquisition financing, D.V.C., J.C.V.-J. (José C. Vera-Jiménez), and J.A.; research, J.C.V.-J. (José C. Vera-Jiménez), D.V.C. and J.A.; validation, J.C.V.-J. (José C. Vera-Jiménez), D.V.C., L.G.H., J.A.Á., A.P.-F. J.G.L, I.M.C., M.L.SNand J.A.; screen, J.C.V.-J. (José C. Vera-Jiménez); methodology, J.C.V.-J. (José C. Vera-Jiménez), D.V.C., J.G.L, I.M.C., M.L.S., J.C.V.-J.(José C. Vera-Jurado) and J.A.; redaction preparation of the original draft, J.C.V.-J. (José C. Vera-Jiménez) and J.A.; Writing—Correction and edition, J.C.V.-J. (José C. Vera-Jiménez) and J.A.; supervision, J.C.V.-J. (José C. Vera-Jiménez), D.V.C., L.G.H.., J.G.L.., J.C.V.-J. (José C. Vera-Jurado), A.P.-F., J.G.L, I.M.C., M.L.S. and J.A. All authors have read and accepted the published version of the manuscript.