RESUMO
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.
RESUMO
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 5âkm 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/Runâ=â3.5±0.9 vs. 2.9±0.6âAU). 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; pâ<â0.05) 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±9.8âkg vs. 93.5±9.9âkg). MP (28.9±2.9 vs. 33.2±7.7âAU), HR (71.6±14.2 vs. 99.0±26.3 bpm), RMSSD (74.8±53.7 vs. 126.5±74.4âms) 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±155.3âms) 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.