RESUMEN
Firefighters must meet certain physical requirements. This study compares the demands of a new firefighting-specific tasks test with an existing laboratory test. Thirty-five male subjects were tested. In both tests, the subjects wore a complete firefighting outfit including breathing apparatus, but not the usual facemask. Test durations were 8 min (existing test) vs ≈10 min (new test). Peak oxygen uptake was similar in the tests, ≈45 ml · kg-1 min-1. The time with an oxygen uptake above 35 ml kg-1 min-1 was longer in the new test, 6.4 vs 4.7 min. The results suggest that the new test is as demanding as the traditional test and offers the advantages of being more specific. The new test could therefore serve as an alternative to the existing test. Based on regression analysis of the two tests, a pass/fail time of 10 min 30 s is suggested.
Asunto(s)
Bomberos , Ejercicio Físico , Prueba de Esfuerzo , Humanos , Masculino , Análisis de RegresiónRESUMEN
Purpose. Physiologic demands of five common tasks in firefighting have been examined. Methods. Eight male volunteers, dressed up as smoke divers (+21 kg extra load), carried out the following tasks at constant pace for 5 min: walking at 1.4 m·s-1, walking (all walks at the same speed) while carrying a 10-kg ladder, walking carrying two hose packs of 16 kg together, walking carrying a 32-kg spreader tool and, finally, climbing up and down a ladder at a preset pace. A 5-min break separated each exercise. The heart rate, oxygen uptake and lung ventilation were measured continuously, and the blood lactate concentration was recorded after each task. Results. The end-exercise heart rate rose from 108 to 180 bpm from the first to last task, blood lactate concentration rose from 1 to 7 mmol·L-1, oxygen uptake rose from 19 to 48 ml·kg-1 min-1 and lung ventilation rose from 38 to 124 L·min-1. Discussion. Walking was an easy task even when dressed up as a smoke diver. Adding loads increased demands; ladder climbing taxed >90% of the subjects' aerobic power. Conclusions. The physiologic demands varied considerably between different tasks.
Asunto(s)
Bomberos , Consumo de Oxígeno/fisiología , Esfuerzo Físico/fisiología , Adulto , Prueba de Esfuerzo/métodos , Frecuencia Cardíaca/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Persona de Mediana Edad , Análisis y Desempeño de Tareas , Adulto JovenRESUMEN
This 9-month randomised controlled workplace physical activity trial investigated the effects of soccer and Zumba exercise, respectively, on muscle strength, maximal jump height, sit-and-reach flexibility and postural sway among female workers. A total of 107 female hospital employees aged 25-63 were cluster-randomised to a soccer group, a Zumba group or a control group. Training was conducted outside working hours as two to three 1-h weekly sessions the first 3 months and once a week the last 6 months. Tests were conducted at baseline, after 3 and 9 months. The soccer group improved maximal neck extension strength both after 3 (1.2 kg; P < 0.05) and 9 months (1.7 kg; P < 0.01) compared to the control group. The Zumba group improved maximal trunk extension strength (3.1 kg; P = 0.04) after 3 months, with improvements in postural sway velocity moment (-9.2 mm(2)/s; P < 0.05) and lower limb lean mass (0.4 kg; P < 0.05) after 9 months. No significant intervention effects were revealed in vertical jump height or sit-and-reach flexibility. The present study indicates that workplace-initiated soccer and Zumba exercise may be beneficial for improvement of the neck and trunk strength, which may have preventive effects with regard to future perceived muscle pain in the respective body regions. Furthermore, the Zumba group revealed positive effects on lower limb lean mass and postural sway compared to the control group.
Asunto(s)
Ejercicio Físico , Actividades Recreativas , Fuerza Muscular , Aptitud Física , Rango del Movimiento Articular , Fútbol , Lugar de Trabajo , Adulto , Composición Corporal , Femenino , Promoción de la Salud , Humanos , Persona de Mediana Edad , Movimiento , Músculo Esquelético , Personal de Hospital , Equilibrio PosturalRESUMEN
Smoke diving is physically demanding, and firefighters must therefore meet certain minimum physical requirements. The aim of this study was to compare the physiological demands of two fire fitness tests: a test of 8-min treadmill walking approved by the Norwegian Labour Inspection Authority (NLIA) (a laboratory test) and a Canadian test consisting of 10 firefighting specific tasks carried out in sequence (an applied field test). If the Canadian field test is as physically demanding as the NLIA-approved laboratory test, it may be suitable for testing Norwegian firefighters. Twenty-two male professional firefighters were tested on separate days. In both tests, the subjects wore a complete firefighting outfit including a breathing apparatus. The test durations were 8 min (NLIA test) versus approximately 6 min (Canadian test). Neither the peak O2 uptake (VO2) of approximately 45 ml kg⻹ min⻹ nor the blood lactate concentration (BLC) at test termination ( ≈ 9 mmol L⻹) differed between the two tests. Rating of perceived exertion (RPE(CR-10)) was lower for the Canadian test than for the Norwegian test (5.2 ± 1.5 vs. 7.0 ± 2.0, respectively), and the exercise time at a high VO2 was also shorter. In conclusion, the Canadian test appeared to be almost as physically demanding as the NLIA-approved test, having equal peak VO2 and BLC, but shorter time at a high VO2 and shorter duration. It might thus be a suitable alternative to the NLIA test with some modifications. The advantage of the Canadian field test is the inclusion of specific firefighting-like tasks that are not part of the NLIA test. PRACTITIONER SUMMARY: The physiological load from two firefighter fitness tests was compared. The demands were found to be similar, but the field test was of a shorter duration. With some modifications, the field test may be sufficiently demanding to be used as a fire fitness test for smoke divers in Norway.
Asunto(s)
Prueba de Esfuerzo , Incendios/prevención & control , Aptitud Física/fisiología , Evaluación de Capacidad de Trabajo , Adulto , Humanos , Ácido Láctico/sangre , Masculino , Persona de Mediana Edad , Consumo de Oxígeno , Esfuerzo Físico/fisiología , Factores de TiempoRESUMEN
In the present study, the density of cell surface beta-adrenergic receptors was determined in different skeletal muscles using the hydrophilic ligand [3H]CGP 12177. The density of beta-adrenergic receptors was highest in the slow-twitch soleus muscle (32.8+/-0.9 fmol mg dw(-1)) and lowest in the fast-twitch glycolytic white gastrocnemius (10.4+/-0.5 fmol mg dw(-1)) beta-Adrenoceptor density correlated closely with the percentage of type-I fibres (r=0.979; P<0.0001) and inversely with the percentage of type-IIB fibres (r=696; P<0.03). Incubation with isoprenaline (10 microM) for 30 min decreased the density of beta-adrenergic receptors in the cell surface from 32.9+/-0.8 to 19.3+/-0.7 fmol mg dw(-1) in the soleus and from 16.8+/-1.0 to 12.0+/-0.7 fmol mg dw(-1) in the epitrochlearis. Internalisation appeared rapid (half-time less than 5 min). To study externalisation of beta-adrenergic receptors, soleus strips were incubated 30 min with 10 microM isoprenaline and then transferred to buffer without agonist. The first incubation reduced the density to approximately 50%, the subsequent incubation without agonist increased cell surface receptor density to approximately 80% of the initial density after 1 h. No further increase was observed over the next 2 h, suggesting that some of the receptors had been degraded. Insulin or contractile activity did not influence rate of externalisation.