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Objectives. The main objective of this study was to evaluate mean propulsive velocity (MPV), mean propulsive force (MPF) and mean propulsive power (MPP) in elite police officers under LOADED and UNLOADED conditions. The study also investigated the association of body composition and strength levels under the same load conditions. Methods. Twenty-one men from an elite unit in Brazil participated in the study, performing Smith machine half squats and an agility test. Dual energy X-ray absorptiometry measured body composition; a linear encoder measured MPV, MPF and MPP during the half squats; and a manual chronometer registered agility test performance. Results. The results showed that wearing and carrying occupational loads did not alter the squat exercise's MPP, MPV and MPF but reduced the performance of relative MPP and agility (p < 0.05). The results also showed that MPP had a higher association with force (i.e., MPF and one-repetition maximum [1RM]) than velocity (i.e., MPV and agility) under the LOADED condition (p < 0.05). Among the body composition variables, only lean body mass was associated with MPP under the LOADED condition (p < 0.05). Conclusion. These findings suggest that load carriage does not reduce absolute mechanical power output, but reduces the relative MPP and agility in military police officers.

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OBJECTIVES: Firefighters work with dogs as support for their search activities for victims. Firefighters who handle dogs supposedly have higher acute muscle pain, more stumbling, and fatigue. This study aimed to verify the influence of a mantrailing dog on the firefighter's psychophysiological and muscular responses and the number of imbalances in a simulated activity of searching for people. METHODS: The sample consisted of 10 canine operators characterized by mass (92.57 ± 9.66 kg), height (1.78 ± 0.06 m), age (37.8 ± 2.1 yr), and length of service (9.5 ± 4.6 yr), who performed a search activity under 2 experimental conditions (dog condition and control condition). The simulated search activity consisted of a predefined hike of 2.5 km between the beginning of a search and the place where the sham victim was hidden. Cardiometabolic variables, pain level, and muscular performance were measured pre and postactivity (time factor). The number of imbalances suffered during hiking was also quantified. RESULTS: ANOVA data indicated interactions (condition × time) related to handgrip strength (P < 0.05). Handgrip strength was reduced in the postsearch activity with the dog, and it increased the control when compared to the preactivity (-12.3% versus +9.2%). Also, the level of pain and discomfort in the neck, trunk, and hip regions was higher with dogs (P < 0.05). Under the dog and control conditions, there were 25 and 05 imbalances, respectively, during the hike. There were no significant differences between the experimental conditions for vertical jump performance and cardiovascular responses either with dog or control. CONCLUSIONS: The findings of this study highlight that a mantrailing dog with the firefighter increased the number of slips, trips, sudden changes in direction, and loss of body balance, accompanied by a reduction in handgrip strength, and increased acute pain in the neck, trunk, and hip. These findings may contribute to support strategies for mitigating injuries and optimizing the performance of canine operators in the fire department and other units cinotechnic.

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Studies on postactivation performance enhancement (PAPE) have used different exercises as a conditioning activity to investigate potentiation, but exclusively in upper limbs (UL) or lower (LL) limbs, or contralateral potentiation. A single exercise capable of inducing PAPE in both UL and LL is currently unknown. The present study explored the effect of the clean and jerk (C&J) as a conditioning activity for simultaneously producing PAPE interlimbs at the fourth, seventh, and 12th minutes postintervention. Twelve male weightlifters with 1-repetition maximum (1RM) in the C&J equivalent to ≥1.15 × body mass were randomly submitted to 2 experimental conditions (C&J and control [CON]). The C&J condition consisted of general warm-up (running on a treadmill and self-selected preparatory exercises) and 4 sets of 3 repetitions of C&J with 2 minutes between them (30%1RM, 50%1RM, 65%1RM, and 80%1RM) followed by a countermovement jump and a bench-press throw on a Smith machine after 4, 7, and 12 minutes, to measure the magnitude of PAPE in UL and LL. No previous exercise preceded countermovement-jump and bench-press-throw tests in the CON besides general warm-up. The main finding was that, regardless of time, the C&J resulted in greater height on countermovement jump and Smith machine bench-press throw when compared with the CON, presenting a similar effect size between UL and LL (34.6 [3.9] vs 33.4 [4.1] cm [+3.66%]; P = .038; effect size = 0.30 and 30.3 [4.7] vs 29.0 [5.1] cm [+4.44%]; P = .039; effect size = 0.26), respectively. Thus, C&J can be useful to produce PAPE simultaneously among members.

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BACKGROUND: Mountain hiking is an unpredictable activity for firefighters during the search, rescue, and firefighting. Could the quality of the uniform worn by firefighters affect psychophysiological variables? OBJECTIVE: The objective of this study was to monitor the responses of perceived exertion (RPE), musculoskeletal pain (MP), and heart rate variability (HRV) responses in firefighters using different uniforms on a 5 km mountain walking activity. The feeling of comfort, safety, and ergonomic adjustment of the two types of uniforms also was verified. METHODS: Sixteen firefighters were divided into two groups: 4thRUPM"B2" (33% polyester and 67% cotton) vs. GOLD (50% polyamide and 50% cotton). The GOLD group wore a prototype that had not yet been operationally tested. RESULTS: The independent t-test showed that the groups had similar results in RPE at post-march (Omni-Walk/Run = 3.5±0.9 vs. 2.9±0.6 AU). ANOVA Two-way (2x group and 2x time) was used to verify differences in body mass (BM), MP, and HRV. There was a main effect of time (pre- vs. post-march; p < 0.05) for BM, MP, heart rate (HR), mean RR, RMSSD, pNN50, and HF, regardless of group (4thRUPM"B2" vs. GOLD). Rainwater increased post-march BM (92.2±9.8 kg vs. 93.5±9.9 kg). MP (28.9±2.9 vs. 33.2±7.7 AU), HR (71.6±14.2 vs. 99.0±26.3 bpm), RMSSD (74.8±53.7 vs. 126.5±74.4 ms) and HF (48.5±20.2 vs. 60.0±16.7 nu) also increased post-march. The mean RR (875.2±153.3 vs. 673.9±155.3 ms) and pNN50 (33.1±18.6 vs. 46.3±23.9%) reduced post-march. There was a subjective preference for GOLD. CONCLUSION: Different uniforms do not compromise psychophysiological variables during the mountain hike but differentiate ergonomic subjectivity.

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The aim of this study was to compare the effects of caffeine ingestion on muscular performance during the early-follicular and mid-luteal phases of the menstrual cycle. Fourteen resistance-trained naturally menstruating women performed countermovement jump (CMJ), maximal voluntary isometric contraction (MVIC), one-repetition maximum (1-RM), and repetitions-to-failure (RF) at 80% of 1-RM in the half-squat exercise, in early-follicular and mid-luteal phases, after placebo or caffeine ingestion. The early-follicular and mid-luteal phases were identified via calendar-based counting method. The MVIC was lower in the early-follicular than mid-luteal phase (-6.2 ± 15.2 N, p < 0.05) and higher with caffeine than placebo ingestion regardless of the menstrual cycle phase (+16.8 ± 26.7 N, p < 0.05). The magnitude of gains (supplement x phase interaction, p < 0.026) in 1-RM, CMJ, and RF with caffeine ingestion was higher in the early-follicular (+16.6 ± 7.1 kg, +2.5 ± 1.6 cm, and +4.5 ± 2.6 repetitions, respectively) than in the mid-luteal phase (+7.7 ± 4.8 kg, +1.5 ± 2.0 cm, and +2.4 ± 3.1 repetitions, respectively). In conclusion, the greater ergogenic effect of caffeine during the early-follicular phase supports its use to mitigate the decline in muscular performance in this phase of the menstrual cycle.

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To investigate the effect of a Trunk Training (TT) program on the general musculoskeletal pain (GMP) and physical performance of Military Police Officers. Twenty officers were divided into either control group (CG) or TT group (TTG). Both groups performed nine weeks of traditional physical training. However, the TTG had 25-minutes allocated to TT during each scheduled physical training period. Anthropometric, trunk endurance, and physical fitness tests were completed pre- and post-training for both groups. Both groups also answered a weekly questionnaire about their GMP. Post-training, trunk endurance performance was significantly higher (p < 0.05) and the GMP significantly lower (p < 0.05) in the TTG when compared to the CG. Improvement in side plank test scores was associated with a decreased in GMP (r = -0.495, p < 0.05). TT can reduce the perception of GMP in addition to increasing the endurance of the trunk muscles. The side plank was the only physical test associated with GMP. Practitioner summary: Trunk Training can reduce general musculoskeletal pain and increase the endurance of the trunk muscles without a concomitant loss in general fitness in elite Military Police Officers. This research lasted 11 weeks and presents real-world and pragmatic findings.

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OBJECTIVE: Military personnel has a large prevalence of back pain, especially those involved in patrolling routines, as they wear heavy protective equipment. Patrolling includes long periods of sustaining the protective equipment in a sitting or in a motor vehicle (motorcycle or car). Thus, understanding spinal loading of military police officers after patrolling by car (CAR; n = 14), motorcycle (MOT; n = 14), and administrative (ADM; n = 14) routines is relevant to establish preventive strategies. METHODS: The torque of the trunk and working and anthropometric characteristics were assessed to explain spinal loading using stature variation measures. Precise stature measures were performed before and after a 6 h journey (LOSS) and 20 min after a resting posture (RECOV). The trunk extensor (PTE BM-1 ) and flexor (PTF BM-1 ) muscles' isometric peak torque were measured before the working journey. RESULTS: The LOSS was similar between CAR and MOT (4.8 and 5.8 mm, respectively) after 6 h of patrolling. The ADM presented the lowest LOSS (2.8 mm; P < .05). No changes in RECOV between groups were observed (P > .05). Vibration may explain the greater spinal loading involved in patrolling in comparison to the ADM. A GLM analysis revealed that BMI was the only explanatory factor for stature loss. No independent variables explained RECOV. The ability of the trunk muscles to produce force did not influence LOSS or RECOV. CONCLUSIONS: Military police officers involved in patrolling may require greater post-work periods and strategies designed to reduce the weight of the protective apparatus to dissipate spinal loading. The external load used in patrolling is a relevant spinal loading factor.

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Background: The ability to produce force is critical to several daily activities. Strategies to reduce delayed onsent muscle soreness (DOMS) and restore force-generating properties that occur in response to training and impair physical performance have been proposed. Acupuncture has been proposed to accelerate recovery and optimize muscle functioning. It was to determine the effects of acupuncture on DOMS and on the muscle force production capacity. Methods: Thirty physically active volunteers (26.3 ± 3.1 years old, 1.70 ± 0.08 m, 66.5 ± 12.6 kg) were allocated in a control (CG; n = 10), placebo (PG; n = 10), and acupuncture (AG; n = 10) groups. The groups were subjected to an exercise protocol to induce DOMS and were assessed for muscle force, threshold, and rate of perceived pain and activation of the biceps brachialis muscle before (PRE) and 20 minutes after (POST) a single acupuncture session using a mixed model analysis. Results: The threshold and rate of perceived pain were reduced in the AG (P < 0.05) but remained unchanged in the other groups (P > 0.05). Muscle activation also showed larger changes in the AG in comparison with the other groups (P < 0.05). No changes in the ability to produce force were found after acupuncture in any groups (P > 0.05). Conclusions: Acupuncture may reduce discomfort and improve muscle activation but was not effective to promote force improvement and/or restore the force-generating properties. It may be speculated that muscle disruption may have played a role and did not allow participants to restore their muscular performance. Rebec Number; RBR-8bh5k7 (www.ensaiosclinicos.gov.br/rg/RBR-8bh5k7); Clinical Trial Registry (UTN No.: U1111-1234-9553).

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O objetivo deste estudo foi desenvolver e analisar a validade de conteúdo, constructo e a fidedigni-dade de um questionário para avaliar a demanda física e operacional, saúde e condições de trabalho em policiais e bombeiros militares. O Questionário de Saúde e Performance para Militares (QSPM) foi desenvolvido por pesquisadores militares e não militares, a validade foi analisada com o índice de validade de conteúdo (IVC), análise fatorial exploratória e a fidedignidade com o percentual de concordância (%C), coeficiente Kappa e alfa de Cronbach. Nove juízes participaram da validação de conteúdo, 732 militares (15% mulheres) participaram da etapa de validação de constructo e 262 militares (18% mulheres) responderam duas vezes ao QSPM para a verificação da fidedignidade. As análises foram realizadas no software SPSS 26 e o nível de significância mantido em 5%. O QSPM apresentou o IVC de 0,98 e variância total explicada em 54,7%. A reprodutibilidade apresentou valores de %C entre 97,2 - 100,0%, Kappa entre 0,94 - 1,00 (p < 0,05) e alpha de Cronbach entre 0,80 - 1,00 (p < 0,05). Conclui-se que o QSPM apresentou validade de conteúdo, constructo e fidedignidade para avaliar a frequência da demanda física e operacional, as condições de saúde e de trabalho de policiais e bombeiros militares

The aim of this study was to develop and analyze the content and construct validity and reliability of a questionnaire to assess the performance, health and working conditions of police officers and military fire-fighters (QSPM). Civilian and military personnel carried out the development of the QSPM. The validity was analyzed by the content validity index (CVI), factor analysis, and the reproducibility by the simple agreement (%SA), the Kappa coefficient, and Cronbach's alpha. Nine experts participated in the content validation, 732 military personnel (15 women) participated in the construct validation, and 262 military (18% women) answered the QSPM twice to measure reproducibility. The QSPM had a CVI of 0.98. In the exploratory factorial analysis, when considering four factors, and the total explained variance was 54.7%. The reproducibility showed %SA values varying between 97.2 to 100.0%, Kappa values varying between 0.94 to 1.00 (p < 0.05 for all questions) and, Cronbach's α values varying between 0.80 to 1.00 (p < 0.05 for all questions). In conclusion, the QSPM showed content validity, construct validity and reliability to measure the frequency of physical-operational demand, the presence of morbidities, and the working condi-tions of police officers and firefighters

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Background: Chronic low back pain (CLBP) is a serious problem in Military Police Officers (MPO), which accounts for up to 45% of the sick leave rates. It has been assumed that the strength and the endurance of trunk flexor and extensor muscles are CLPB key factors, but it is not known whether these attributes are related to pain intensity. It was aimed to determine whether the strength and endurance of trunk flexor and extensor muscles differ in MPO with no pain (CON; n = 24), moderate (MOD; n = 42), and severe (SEV; n = 37) nonspecific chronic low back pain (CLBP). Methods: The peak torque and endurance test of trunk flexor (PTF.BM-1) and extensor (PTE.BM-1) muscles were compared. A multiple regression analysis was used to identify pain intensity predictors in all groups (PAIN) and according to pain intensity (MOD and SEV). Results: The PTF.BM-1 was negatively related to pain and was a significant predictor, irrespective of pain intensity (PAIN). Conclusion: When pain intensity was considered the PTF.BM-1 and PTE.BM-1 explained the pain in the MOD, while the PTE.BM-1 and service time explained pain intensity in the SEV. Endurance of the flexor and extensor muscles was not related to pain intensity. These results indicated that training protocols must emphasize specific strengthening routines.

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