Physical Training Programs for Tactical Populations: Brief Systematic Review

This review aims (i) to identify and analyze the physical training programs used for tactical personnel (TP) and (ii) to understand the effects of physical training programs on the health and fitness, and occupational performance of tactical personnel. A literature search used the keywords ‘Physical Training Program’, ‘Police’, ‘Law Enforcement’, and ‘Firefighter’. A total of 23 studies out of 11.508 analyzed were included. All studies showed acceptable methodological quality in assessing physical fitness (PF), and training programs’ effect sizes (Cohen’s d) on PF attributes were calculated. The results showed that physical training programs (duration > four weeks) can improve (medium-to-large effects) (i) measures of physical fitness and (ii) performance in simulations of occupationally specific tasks. This review provides summary information (i) to help select (or adjust) physical training programs for TP and (ii) to clarify the effect of different occupational-specific training interventions on fitness measures and health-related parameters for TP.


Introduction
Tactical populations (e.g., police officers, firefighters, and military) have their specific tasks, which are complex, varied in nature, unpredictable, and highly demanding from a physical fitness point of view [1].
This personnel executes, in the performance of their mission, a wide variety of actions, many of which are physical, where they may be required to: stop suspects, run, climb up/downstairs, pull, push, overcome obstacles, chase suspects, and use weapons from a vast panoply of options [2]. To perform these activities, tactical personnel require endurance, strength, speed, agility, and flexibility to undertake their profession [3].
To respond to this large number of actions and perform their mission efficiently, the tactical population (TP) must have a physical fitness (PF) that is up to the enormous challenges of the demanding professions. In addition, it is also of great importance that TP is in good PF condition. Otherwise, they can endanger the safety of the community or even their own safety [4].
There is considerable scientific evidence that the PF of this TP is below the general population and health recommendations [5][6][7]. It has been extensively studied and shown that physical components such as cardiorespiratory fitness, muscular strength, and others are closely related to health parameters and improved quality of life and, consequently, enhanced job skills [8][9][10]. In accordance, a decline in exercise practice has implications for the health of TP, which ultimately impacts the organizations themselves (lower productivity levels [11]), given they are one of their greatest assets.
Nevertheless, there is only one study on physical activity and the application of specific training programs in TP in Portugal. Therefore, this review aims (i) to identify and analyze the most used PF programs for TP and (ii) to understand their impact on the development of PF attributes associated with performing the function.

Experimental Approach to the Problem
The present work was conducted to identify the PF programs most used in scientific research with PT and to determine their impact on their physical abilities in performing their functions. The guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model [12] were followed. The present study is exempt from ethical approval because the data came from previously conducted studies for which the authors of each study had obtained approvals.
Databases were selected because they were high-quality, peer-reviewed articles that represented journals relevant to the topic of the study. We used specific terms and filters for the databases searched, which are summarized in Table 1.

Databases Search Terms Filters (Sort By) Results
PubMed "Physical Training Program" AND "Police" OR "Law Enforcement" OR "Firefighter" Best Match 8581 SPORTDiscus|EBSCO "Physical Training Program" AND "Police" OR "Law enforcement" OR "military" OR "firefighters" Relevance 2927 Eligibility criteria were defined and applied to each database to refine the search results. The defined inclusion criteria were individuals from police, fire, or other law enforcement agencies who have participated in a training program. The specified exclusion criteria were: (i) studies older than ten years; (ii) studies examining only body composition; and (iii) instrument development and validity studies. Duplicate studies were removed after all studies were collected. The screening and selection process is described in a PRISMA flow diagram ( Figure 1) [12].

Critical Appraisal
To assess the methodological quality of the studies, we used the NHLBI guidelines, which consist of a checklist of 14 questions. Each question can be answered "Yes", "No", "Not applicable", "Not reported", or "Cannot be determined". Two authors also guaranteed methodological quality to avoid bias. Table 2 shows the quality of all studies in this review.

Critical Appraisal
To assess the methodological quality of the studies, we used the NHLBI guidelines, which consist of a checklist of 14 questions. Each question can be answered "Yes", "No", "Not applicable", "Not reported", or "Cannot be determined". Two authors also guaranteed methodological quality to avoid bias. Table 2 shows the quality of all studies in this review.

Data Extraction
Afterwards, the articles were critically analysed, and the following information was extracted: authors and year of publication; study population; measurements (PF tests); physical training program; main results/general conclusions. All information is presented in Table 3. In continuation, the mean and standard deviations (SDs) for fitness test results (pre-and post-intervention) in each selected study were used to calculate the effect size (Cohen's d) and effect size correlation (r) of the physical training programs on fitness measures (note that d and r are positive if the mean difference is in the predicted direction).    16-wk progressive training program reveals that overall indices of physical fitness improved in more than 89% of the population, depending on the specific fitness outcome. At 8 wks into the program while scores showed improvement and continued over the 16 wk period.

Search Results
A total of 11,508 studies were identified. After being screened by titles, abstracts, and complete text analyses, 23 studies were considered (Table 3). We summarized the screening and selection process in the PRISMA flow diagram (Figure 1) and the literature search results [12].

Discussion
The aims of this review were (i) to identify and analyze the most-used PF programs for TP and (ii) to understand their impact on the development of physical abilities associated with the performance of the function.
All studies showed acceptable methodological quality in assessing PF and the physical training program.
In almost all programs, we observe a combination of various types of exercises, with body weight or using external loads (weights) combined with cardiovascular training.
Overall, the studies included in this review have shown that a physical training program could significantly improve tactical populations' PF.
Despite the diversity and different options of the physical training programs, all of them proved fruitful since, in all the studies, improvements were observed in the motor skills evaluated and the health measures themselves.
In the study by Bonder et al. [28], they did not observe significant improvements in the sprint, perhaps because too short a training program (only four weeks) was applied, which could indicate that training programs in these areas need to be longer in duration or performed more times per week to provoke improvements, as noted by Lahti et al. [35], in a study they conducted with soccer players on speed. These authors suggest that training of at least eight weeks, 1 to 2× per week, should be applied to observe improvements. This is consistent with our findings, where most studies with more minor interventions had smaller effect sizes on PF performance tests.
We could conclude from this review that studies with less than eight weeks may not be sufficient to show significant differences [28]. Still, studies with more than 16 weeks are extensive and show little changes compared to TP between 9 and 15 weeks [15,19,23,32,34]. Thus, we can conclude that TP adjusted between 9 and 15 weeks show significant differences in PF [3,13,16,[24][25][26].
In strength work, whether through a weight or bodyweight training program, we can see that improvements have been observed in short periods. Even in the study by Chizewski et al. [29], improvements were observed in only seven weeks. These results are like those obtained by Munn et al. [36], who also eyed improvements in strength capacity in only six weeks.
In the study by Cocke et al. [16], the randomized training group significantly improved all parameters. In contrast, the periodized group observed significant improvements in only three outcome measures (push-ups, sit-ups, and 300-m sprint). Periodized training does not provide additional improvements. Nevertheless, this information needs to be carefully analyzed as it contrasts with the study by Knapik et al. [37] that observed improvements in both periodized and randomized training groups.
Rossomanno et al. [13] and Lan et al. [24], who observed in their study several improvements in the training program applied after the end of the training program, when they reapplied the battery of tests sometime later, observed regression in the results obtained, both in the trials and in terms of health measures. In this sense, to ensure that police officers are prepared to perform their duties on the job, it is recommended that police departments provide a regular, supervised, job-based exercise program throughout the year [13].
Physical activity must be part of the daily routine for TP so that they improve or at least maintain high levels of PF that are essential for mission performance. The program must be supported throughout their lives because more is needed for TP to have physical activity during the course and not any physical activity at work.
However, a limitation of this review was the small number of studies analyzed. Initially, the idea was to critically review studies in which the sample consisted of police officers. However, after determining that there were very few studies of this type, it was decided to include studies in which the sample included so-called TP (i.e., tactical athletes). In addition to police officers, studies involving firefighters and military personnel were included, and studies involving cadets/recruits and cadets who are not yet TP were also included. Another limitation of these studies was the different methodological characteristics of each study (other test batteries), the different duration and frequency of use of the training, and the studies with different sexes when the results are presented in standard averages; therefore, the results here are weakened. This promotes considerable variability in the results with the small number of studies.
The content of this review is essential because it informs those responsible for developing training programs for tactical populations, which tests are most applied, and which training programs show the best results.
We consider it essential to develop a study like those analyzed [application of a training program to tactical populations] in Portugal to understand if the applications are transversal or if adaptations are necessary for the Portuguese context.

Conclusions
All studies included in this critical review have been evaluated as fair-to-sound quality, proving that training programs of varied frequency and exercise type can help improve required fitness testing results and optimize job performance.
To be effective, physical training programs should last at least eight weeks and have a weekly frequency of at least three times. Programs that combined strength training with cardiovascular training were shown to be more effective in creating positive changes in outcome measures and included exercises such as push-ups, running, bench press, front and back squats, burpees, lunges, sprints, and work-specific simulations (e.g., loaded run and dummy drag).
Because of their physically demanding work, TP needs specific training programs for their activity, which must remain throughout their career.
After a survey of studies conducted in this scope, only one investigation was observed in Portugal with a training program applied to TP. Therefore, conducting more studies to provide TP with adequate exercise for their functions is necessary. It is also essential to conduct a study with the long-term fitness and health outcomes of a randomized vs. periodized approach to clarify if traditional programs provide (or not) additional benefits over periodized exercise programs.