Cardiorespiratory fitness in police recruits: Assessing the validity of the 20-meter shuttle run test for recruitment purposes

BACKGROUND: Although the 20-meter shuttle run test (20MSR) is frequently used by police organisations for recruitment purposes, to our knowledge no study has yet assessed the accuracy of this test to estimate maximal oxygen consumption (VO2max) in police recruits. OBJECTIVE: The primary objective of this study was to assess the validity of the 20MSR as a predictor of VO2max in police cadets. METHODS: 49 police cadets completed both an indirect calorimetry VO2max assessment and a 20MSR. Based on their results, estimated VO2max was calculated using an established equation. Furthermore, two models estimating the VO2max was also developed using the final stage completed and sex as independent variables in the first model (model A) as well as the final half-stage completed and sex in the second model (model B). RESULTS: A strong and significant bivariate correlation was found between measured VO2max and the final stage completed at the 20MSR (r = 0.874, p < 0.001). Nevertheless, limits of agreement analysis showed relatively large agreement errors between measured VO2max and estimated VO2max based on the established equation (0.46±6.29 ml·min–1·kg–1), model A (0.00±5.58 ml min–1 kg–1), and model B (0.00±5.48 ml min–1·kg–1). CONCLUSIONS: Although the 20MSR can be a useful tool to estimate cardiorespiratory fitness for research and conditioning purposes, the large agreement errors found in this study suggest that results at the 20MSR should be interpreted with caution when making “pass or fail” decisions.

Development of physical employment standards of specialist paramedic roles in the National Ambulance Resilience Unit (Naru)

AIM

To develop evidence-based role-specific physical employment standards and tests for National Ambulance Resilience Unit (NARU) specialist paramedics.

METHODS

Sixty-two (53 men, 9 women) paramedics performed an array of (1) realistic reconstructions of critical job-tasks (criterion job performance); (2) simplified, easily-replicable simulations of those reconstructions and; (3) fitness tests that are portable and/or practicable to administer with limited resources or specialist equipment. Pearson's correlations and ordinary least products regression were used to assess relationships between tasks and tests. Performance on reconstructions, subject-matter expert and participant ratings were combined to derive minimum acceptable job performance levels, which were used to determine cut-scores on appropriate correlated simulations and tests.

RESULTS

The majority of performance times were highly correlated with their respective simulations (range of r: 0.73-0.90), with the exception of those replicating water rescue (r range: 0.28-0.47). Regression compatibility intervals provided three cut-scores for each job-task on an appropriate simulation and fitness test.

CONCLUSION

This study provides a varied and easily-implementable physical capability assessment for NARU personnel, empirically linked to job performance, with flexible options depending on organisational requirements.

Fitness components associated with performance of a law enforcement physical employment standard in police cadets

BACKGROUND

The physical preparation of cadets for both PES and police job performance is a major concern for police organisations. Identifying fitness components associated with both PES performance and work performance can provide essential information for the physical training of police cadets. Therefore, the objective of this study was to assess the association of fitness components with performance of the Standardized Physical Abilities Test (SPAT), a new law enforcement PES.

METHODS

A sample of 41 police cadets was recruited to take part in this cross-sectional study. First, the participants were assessed using six fitness assessments (standing broad jump, medicine ball put, grip strength test, visuomotor reaction time (VMRT) test, modified agility T-test, and 600-meter run). In a second experiment, participants performed the SPAT.

RESULTS

Bivariate correlation analysis showed moderate to strong associations between each fitness assessment and SPAT performance. Based on stepwise multiple regression analysis, results at the VMRT test, the medicine ball put, and the agility T-test accounted for 66.0% of the variability in SPAT performance (R2 = 0.660; p < .001).

CONCLUSIONS

Overall, our results suggest that exercise prescriptions for police cadets should focus on power, agility, and VMRT. Furthermore, our results show that performance in a PES can be estimated rather precisely based on low-cost fitness assessments. Therefore, such methodology could be used to develop fitness assessments specific to PES requirements.

Does body size impact muscle recruitment during law enforcement physical control simulator use?

This study examined muscle activation during the 'push-pull' component of law enforcement physical abilities testing and assessed activation differences based on sex, height, and body mass index. Fifty participants (40 male) completed the 'push-pull' task while surface electromyograms were recorded from ten upper and lower extremity muscles, and six trunk muscles. Muscle activation was amplitude-normalized to maximum voluntary isometric contraction and compared between sexes and tertiles of height and body mass index (BMI). Women had significantly higher activation of anterior deltoid and pectoralis major on the pull, and posterior deltoid and triceps on the push. Significant differences largely remained after controlling for body size in regression analyses. The lowest tertile of height had significantly higher triceps activity on the push. The highest tertile of BMI had significantly higher rectus abdominus and external obliques activity on the pull, and external obliques activation on the push. Practitioner summary: Muscle activation during the 'push-pull' component of law enforcement standardised testing was examined, including differences based on sex, height, and BMI. Minimal differences existed between sexes (females had higher deltoid, pectoralis major, triceps activity), height (shorter people had higher triceps activity) and BMI tertiles (larger people had more abdominal activity). Abbreviations: ANOVA: analysis of variance; BMI: body mass index; COPAT: correctional officer's physical abilities test; EMG: electromyogram; IMU: inertial measurement unit; MVIC: maximum voluntary isometric contraction; PARE: physical abilities requirement evaluation; PCS: physical control simulator; POPAT: police officer's physical abilities test; RMS: root mean square.

The Association Between Fitness Test Scores and Musculoskeletal Injury in Police Officers

A police officer’s career is hazardous and physically demanding. In order to perform occupational tasks effectively and without injury, officers require adequate physical abilities. The aim of this study was to investigate the relationship between scores on several fitness tests and musculoskeletal injury in a group of municipal police officers. This retrospective study used existing data to examine the relationship between risk of injury and fitness test performance. Injured and uninjured police officers scored significantly differently on several fitness measures. A multivariate regression indicated that a combination of age, sex, number of pull ups completed and maximal oxygen consumption (VO_2max) best explained injury risk. Additionally, the findings indicated an interaction between sex and VO_2max, and so the effect of VO_2max on injury risk cannot be understood without accounting for sex.

Cross-Sectional and Retrospective Cohort Analysis of the Effects of Age on Flexibility, Strength Endurance, Lower-Body Power, and Aerobic Fitness in Law Enforcement Officers

Lockie, RG, Dawes, JJ, Kornhauser, CL, and Holmes, RJ. Cross-sectional and retrospective cohort analysis of the effects of age on flexibility, strength endurance, lower-body power, and aerobic fitness in law enforcement officers. J Strength Cond Res 33(2): 451-458, 2019-There can be a great age range in cohorts of law enforcement officers. As the tasks required of officers generally do not change with advancing age, it is important to understand how physical performance in tests that assess job-specific characteristics may be altered. Retrospective analysis of performance test data of 383 officers (362 men and 21 women) was conducted. The tests included the following: sit-and-reach to determine hamstring and lower back flexibility; maximal push-up and sit-up repetitions in 60 seconds to measure muscle endurance; vertical jump (VJ) to assess lower-body power; and 2.4-km run to ascertain aerobic capacity. Data were stratified by age into 20-29, 30-39, 40-49, and 50-59 year groups, and analyzed by sex. A 1-way analysis of variance with the Bonferroni post hoc test was used to calculate the differences between the groups. Considering the male subjects, the 40-49 and 50-59 year groups performed poorer in the VJ, sit-up test, and 2.4-km run compared with the 20-29 year group (p ≤ 0.001-0.045). For the female subjects, the 20-29 year group was superior to the 30-39 (p = 0.013) and 40-49 (p = 0.025) year groups in the push-up test. To ensure that an older officer can successfully complete occupation-specific tasks, lower-body power, abdominal strength, and aerobic training should be completed. Female officers should also attempt to maintain relative upper-body strength. Practitioners must attempt to design training programs that fit within the context of the occupational demands, and potentially using a nontraditional training design as law enforcement officers may not have the time to follow a traditional periodization model.

The Ottawa Paramedic Physical Ability Test: test-retest reliability and analysis of sex-based performance differences

The Ottawa Paramedic Physical Ability Test (OPPAT) is a physical employment standard (PES) that candidates must pass as a pre-hire requirement and that incumbents may have to pass prior to returning to work after absence, to demonstrate their physical capabilities as required to safely meet the demands of paramedic work. Consistent with best practice guidelines for PES development, it is important to establish reliability and to investigate sex-based performance differences. Active duty paramedics completed the OPPAT twice while candidates completed the OPPAT six times. Across all participants, a median improvement of 76.0 s was observed in OPPAT performance (922.0-846.0 s) between trial 1 and trial 2. Among candidates, OPPAT performance stabilised by the fourth trial confirming reliability. Sex-based analyses revealed median differences in OPPAT performance time of 39.0 and 63.0 s between males and females during the first and second trials respectively. Practitioner summary: Active duty paramedics and candidates performed the Ottawa Paramedic Physical Ability Test (OPPAT) faster following familiarisation. Among candidates, performance time stabilised by the fourth trial. Performance time was slower among females, but this had less impact on females' ability to meet the OPPAT standard.

The effect of general duty police ensemble on graded exercise and simulated work performance

This 2-part study examined the impact of general duty police ensemble on selected cardiopulmonary responses during incremental treadmill exercise and on simulated work performance in 25 healthy young male and female participants. Part I comprised randomly ordered treadmill tests in 2 experimental conditions: physical training (PT; undergarments, shorts, t-shirt, and running shoes) and police duty ensemble (PDE; undergarments, body armour, patrol uniform, boots, duty belt with required equipment, radio, and weapons). The PDE added 10.3 kg (SD 0.4) or 14% (SD 2) body mass. Participants walked at 5.6 km·h^-1, starting at 0% grade with 2% increases in grade every 2 min. The 4% stage was 6 min in duration to achieve physiological steady state. Subsequently, the 2-min increments continued to exhaustion. Part II evaluated performance time on a recognized job-related work simulation circuit, in 3 experimental conditions: (i) PT, (ii) weighted belt (WB; PT plus a 7.5 kg weighted belt), and (iii) PDE. In Part I, physiological responses (e.g., oxygen uptake, ventilation, heart rate) were elevated (p < 0.05) with PDE during submaximal exercise but peak values were unchanged. Test duration and peak power output were significantly reduced with PDE. In Part II, circuit completion time was increased in PDE but not WB when compared with PT (p < 0.05). Heart rate and perceived exertion were similar in all conditions and perceived dyspnea was higher in PDE. Novelty Police duty ensemble negatively affected exercise performance more than would be expected due to load mass alone. Specificity must be considered when simulating occupational load carriage.

Evaluating the effect of a strength and conditioning program to improve paramedic candidates' physical readiness for duty

BACKGROUND

The Ottawa Paramedic Physical Ability Test (OPPAT™) is a physical employment standard for the paramedic sector. If a candidate is unsuccessful in meeting the OPPAT™ performance standard they should be provided with an appropriate accommodation, such as a strength and conditioning program, to improve performance.

OBJECTIVE

Develop, implement and evaluate the effectiveness of a 4-week strength and conditioning program on improving OPPAT™ performance and associated fitness measures in paramedic candidates.

METHODS

A 4-week strength and conditioning program was developed to focus on strength and power improvements. Based on initial OPPAT™ performance, participants were divided into high and low performing groups; only the low performing group received the training intervention. OPPAT™ completion times and relevant fitness measures were compared pre- to post- intervention and between groups.

RESULTS

Over the 4-weeks, peak lower body power and grip strength did not significantly improve in the intervention group, however OPPAT™ performance improved by 10%. The control group had significantly lower OPPAT™ completion times both pre- and post-intervention (19% and 11% lower respectively), as well as greater grip strength and peak lower body power.

CONCLUSIONS

Implementation of a targeted strength and conditioning program successfully improved OPPAT™ performance in low performing candidates.

Physical employment standard for Canadian wildland fire fighters; identifying and characterising critical initial attack response tasks

Physical employment standards evaluate whether a worker possesses the physical abilities to safely and efficiently perform all critical on-the-job tasks. Initial Attack (IA) wildland fire fighters (WFF) must perform such critical tasks in all terrains. Following a physical demands analysis, IA WFF (n = 946 out of a possible 965) from all fire jurisdictions ranked the most demanding tasks and identified mountains, muskeg and rolling hills as the most challenging terrains. Experimental trials found the oxygen cost (mean ± SD V˙ O₂ mL·kg^-1·min^-1) while performing the hose pack back carry to be 40 ± 7 in steep mountains, 34 ± 5 in muskeg and 34 ± 2 in rolling hills (n = 168). Back-carrying and hand-carrying a 28.5 kg pump, back-carrying a 25 kg hose pack and advancing charged hose were the most demanding tasks. Performing the same emergency IA WFF tasks was significantly more demanding in mountains (p ≤ 0.05), and these higher demands must be taken into account when developing a physical employment standard for Canadian wildland fire fighters. Practitioner Summary: Physical employment standards evaluate whether an applicant or incumbent possesses the physical and physiological abilities to safely and efficiently perform the critical on-the-job tasks. This paper details the process used to undertake a physical demands analysis and characterise tasks for the development of a  circuit test and fitness employment standard for IA WFF.

Identifying the critical physical demanding tasks of paramedic work: Towards the development of a physical employment standard

Public safety related occupations including police, fire and military commonly apply physical employment standard (PES) to facilitate job matching, an approach to evaluate if candidates demonstrate acceptable physical capabilities as required to perform the job safely and effectively. In Canada, paramedics remain as one of the few public safety occupations without an evidence-based, validated PES. The purpose of this study was to document and describe the physical demands of paramedic work and to identify the most physically demanding tasks. These outcomes are essential to inform the design and development of an evidence-based PES for the paramedic sector. Physical demands of paramedic work were documented and described using a direct observation-based task analysis technique. Five paramedic's were trained to document the physical demands of their work, then applied their training to observe more than 90 calls over the course of 20 full 12-h work shifts. Physical demands data were then listed in a survey, administered service-wide, where 155 frontline paramedics identified critically demanding tasks and rank-ordered physical demands from not physically demanding to very strongly demanding. Critically important and physically demanding tasks were identified such as: transferring a patient; loading or unloading a stretcher in to or out of the ambulance; performing CPR; and, raising and lowering a stretcher. It is important that a paramedic-based PES evaluate a candidate's physical capabilities to perform the critical and physically demanding tasks identified in this study.

The application of subjective job task analysis techniques in physically demanding occupations: evidence for the presence of self-serving bias

The aim of this study was to determine if perceptions of physically demanding job tasks are biased by employee demographics and employment profile characteristics including: age, sex, experience, length of tenure, rank and if they completed or supervised a task. Surveys were administered to 427 Royal Australian Navy personnel who characterised 33 tasks in terms of physical effort, importance, frequency, duration and vertical/horizontal distance travelled. Results showed no evidence of bias resulting from participant characteristics, however participants who were actively involved in both task participation and supervision rated these tasks as more important than those involved only in the supervision of that task. This may indicate self-serving bias in which participants that are more actively involved in a task had an inflated perception of that task's importance. These results have important implications for the conduct of job task analyses, especially the use of subjective methodologies in the development of scientifically defensible physical employment standards. Practitioner Summary: To examine the presence of systematic bias in subjective job task analysis methodologies, a survey was conducted on a sample of Royal Australian Navy personnel. The relationship between job task descriptions and participant's demographic and job profile characteristics revealed the presence of self-serving bias affecting perceptions of task importance.

Variability in performance on a work simulation test of physical fitness for firefighters

The Canadian Forces Firefighter Physical Fitness Maintenance Evaluation (FF PFME) requires firefighters in full fire-protective ensemble, including self-contained breathing apparatus, to correctly complete 10 work-related tasks on a measured and calibrated course. Fitness for duty is inferred from completion time of the course. We hypothesized that completion time may be dependent on pacing strategy and day-to-day fluctuations in biological function. To examine variability in performance, 20 females and 31 males (mean ± SD; age, 27.6 ± 10.5 years; height, 176.7 ± 8.3 cm; mass, 77.3 ± 13.4 kg) were familiarized with the FF PFME and then completed the test on 6 separate days. Pre-test behaviours (e.g., sleep, diet) and test conditions (e.g., calibration, time of day) were consistent. Repeated-measures ANOVA revealed a significant decrease in completion time between tests 1 and 6 (18.7%) and between all sequential pairs (e.g., tests 1 and 2). There was also a small but significant increase in the fraction of total test time for task completion and a corresponding decrease in the time to transition between tasks. The performance improvements cannot be explained by differences in effort (heart rate and perceived exertion). Coefficient of variation for tests 1, 2, and 3 was 7% and for tests 4, 5, and 6 was 2.6%. The results indicate the importance of practice on performance and the potential for false-positive or false-negative decision errors if biological variability is not taken into account.