The present study was to evaluate endothelial nitric oxide synthase (eNOS) protein expression and hemodynamics of pulmonary circulation in rats of "Living high and Training low" (LH+TL). The Sprague Dawley strain of male rats were used at the age of 9 weeks. They were divided according to four conditions of a living low (LL) group, living low and training low (LL+TL) group, living high (LH) group and LH+TL group, for 10 days. We assessed the effects of LH+TL on exercise-induced pulmonary arterial pressure and blood lactic acids under sea-level altitude in catheter-implanted conscious rats. Also, we measured the pulmonary artery under anesthesia and analyzed eNOS protein expression by western blot analysis. The blood lactate levels in the LH+TL rats decreased after maximal treadmill running compared to LL, LL+TL and LH rats (p<0.05). The increase in pulmonary arterial blood pressure with exercise was significantly lower in the LH+TL group than in the LL group (p<0.05). The eNOS protein expressions of pulmonary artery were higher in the LH+TL group than in the LL group (p<0.05). This study indicates that LH+TL reduced the increase of pulmonary arterial blood pressure with exercise at below sea-level altitude. In addition, eNOS protein expressions were enhanced in the pulmonary arteries of LH+TL rats. Thus, we conclude that the high altitude training of LH+TL was a useful method for improvement of endurance exercise ability and this improvement may be associated with pulmonary arterial response.

The purpose of this study was to investigate the characteristics of running on self-driven treadmill equipped with curve-shaped bed (TM) from kinematics and kinetics variables by comparing with those obtained on overground running (OG). Eight healthy male subjects run on TM and OG under constant speed condition of 3m/s. Thirty five reflective anatomical landmarkers were attached on the subject according to Plug-in-gait model. Kinematics and kinetics data were recorded during stance phase using VICON MX (200fps) motion capture system and Kistler force plate (1kHz). Running spatio-temporal parameters such as stride length /stride frequency, lower limb joint kinematics and ground reaction force were compared between TM and OG conditions. Significant high stride frequency on TM running was indicated compare with OG condition (P<0.05). Contact time were almost same between TM and OG, whereas in vertical ground reaction force, non-first impact force as well as lower average loading rate were indicated in TM compared to OG (P<0.05). Lower joint kinematics were significantly different between TM and OG running during first 20% stance phase of normalized stance time. Hip and knee flexion angular velocities were larger in OG than TM (P<0.05). These results suggest that TM running causes lowed intensity for lower limb joints during stance phase, which might be applicable for prevention of running injury.