RESUMO
High skin temperatures reduce the thermal gradient between the core and the skin and they can lead to a reduction in performance and increased risk of injury. Graduated compression stockings have become popular among runners in the last years and their use may influence the athlete's thermoregulation. The aim of this study was to investigate the effects of graduated compression stockings on skin temperature during running in a moderate indoor environment. Forty-four runners performed two running tests lasting 30min (10min of warm-up and 20min at 75% of their maximal aerobic speed) with and without graduated compressive stockings. Skin temperature was measured in 12 regions of interest on the lower limb by infrared thermography before and after running. Heart rate and perception of fatigue were assessed during the last minute of the running test. Compression stockings resulted in greater increase of temperature (p=0.002 and ES=2.2, 95% CI [0.11-0.45°C]) not only in the body regions in contact (tibialis anterior, ankle anterior and gastrocnemius) but also in the body regions that were not in contact with the garment (vastus lateralis, abductor and semitendinosus). No differences were observed between conditions in heart rate and perception of fatigue (p>0.05 and ES<0.8). In conclusion, running with graduated compression stockings produces a greater increase of skin temperature without modifying the athlete's heart rate and perception of fatigue.
Assuntos
Corrida/fisiologia , Temperatura Cutânea/fisiologia , Meias de Compressão , Adulto , Atletas , Regulação da Temperatura Corporal/fisiologia , Fadiga/etiologia , Fadiga/fisiopatologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , MasculinoRESUMO
The CO2 catalytic reduction activities of four different Co-modified Ni-based catalysts derived from hydrotalcite-like materials (HTCs) prepared by co-precipitation method were investigated under thermal and photocatalytic conditions. All catalysts were tested from 473 to 723 K at 10 bar (abs). The light intensity for photocatalytic reactions was 2.4 W cm-2. The samples were characterized to determine the effect of morphological and physicochemical properties of mono-bimetallic active phases on their methanation activity. The activity toward CO2 methanation followed the next order: Ni > Co-Ni > Co. For the monometallic Ni catalyst an increase of a 72% was achieved in the photo-catalytic activity under UV and vis light irradiation at temperatures lower by > 100 K than those in a conventional reaction. Co-modified Ni based hydrotalcite catalysts performed with stability and no deactivation for the 16 h studied under visible light for methanation at 523 K due to the presence of basic sites.
RESUMO
OBJECTIVE: Foot orthoses are increasingly used by runners despite the controversy about whether their use can reduce the risk of overuse injuries. Some authors have found modifications in plantar pressures with the use of foot orthoses, which could produce changes in the surface skin temperature of the foot soles. The aim of this study was to analyse the effects of custom-made and prefabricated foot orthoses on the skin temperature of different regions of both foot soles after running. APPROACH: Twenty-four participants carried out a maximal aerobic speed test as a pre-test, and three running tests at the laboratory wearing different foot orthoses conditions (control, prefabricated and custom-made) previously randomized. Skin temperature of four regions of interest of the foot soles was assessed before, immediately after and ten minutes after running. MAIN RESULTS: The use of prefabricated and custom-made foot orthoses did not produce changes on skin temperature of the foot soles neither in absolute temperatures (p > 0.05), nor in temperature variations: between immediately after and before running (p > 0.05), and between ten minutes after and immediately after running (p > 0.05). Otherwise, higher values were found with no insoles than with prefabricated foot orthoses, 10 min after running in relation to before running, in forefoot [mean (standard deviation): 5.6 (2.4) versus 3.7 (2.7) °C; p = 0.02; effect size (ESd) = 0.72], midfoot [3.7 (1.5) versus 2.7 (1.5) °C; p = 0.03; ESd = 0.65] and rearfoot [4.18 (2.05) versus 2.9 (1.82) °C; p = 0.02; ESd = 0.64)]. SIGNIFICANCE: In conclusion, the use of foot orthoses, in general, does not affect the surface skin temperature of the foot soles after an intense run.