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This study examined the physiological responses to cold stimulus during intermittent high-intensity exercise simulating on-snow alpine ski training. 7 male alpine skiers performed intermittent high-intensity exercises composed of 4 bouts of cycling exercise at 140 % V̇O2max intensity for 30 s with 10-min rests on a cycle ergometer in cold (1 °C) and control (22 °C) conditions. The subjects wore racing suits, middle layers and half pants designed for alpine skiers. Rectal temperature and mean skin temperature were lower in the cold condition than in the control condition (36.8 ± 0.5 vs. 37.1 ± 0.1 °C and 28.4 ± 0.6 vs. 33.3 ± 0.6 °C, respectively). Oxygen consumption during rests and the last 2 bouts of exercise was higher in the cold condition than in the control condition. Although plasma noradrenaline and serum triglyceride were higher in the cold condition than in the control condition, plasma glucose, adrenaline and serum glycerol were lower. Serum free fatty acid and plasma lactate concentrations did not differ significantly between the 2 conditions. These results indicate that a cold stimulus affects body temperature and energy metabolism and may lead to a decrease in exercise capacity in alpine skiers during on-snow training. [ABSTRACT FROM AUTHOR]

To examine the effect of long-term daily training on athletes' skeletal muscle, this study determined the relation between their muscle thickness and passive muscle stiffness, and compared the muscle thickness and muscle stiffness between athletes and non-athletes. Participants were elite Japanese athletes (278 men, 200 women) from various sports and non-athletes (35 men, 35 women). Rectus femoris (RF) muscle thickness was measured using B-mode ultrasonography and was normalized to the total body mass (muscle thickness/body mass 1/3 ). RF passive muscle stiffness (shear modulus) was assessed by ultrasound shear-wave elastography. There was a negligibly significant correlation between muscle thickness and muscle stiffness in male athletes ( p =0.003; r=-0.18) but not in female athletes ( p =0.764; r=0.02). Among men, muscle thickness was significantly greater in athletes than non-athletes ( p <0.001), whereas muscle stiffness was significantly less in athletes than non-athletes ( p =0.020). Among women, muscle thickness was significantly greater in athletes than non-athletes ( p <0.001), whereas muscle stiffness did not differ significantly between athletes and non-athletes ( p =0.412). These results suggest that the effect of long-term daily training performed by athletes on muscle stiffness is more complicated than that on muscle thickness., Competing Interests: The authors declare no conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)