刺五加制剂的人体抗疲劳试验与小鼠负重游泳试验的比较

为研究刺五加制剂的抗疲劳作用，在小鼠游泳试验基础上于１６名健康成年男子中研究递增运动负荷下刺五加制剂对人体运动能力的影响。结果表明，服用刺五加制剂后可提高无氧阈下作功能力１２．４％；呼吸商由０．９９下降至０．８６，使运动时脂肪供能增加４３％。又在２０名大学生中进行持续恒定负荷运动测试，结果表明在４５０ｋｇ．ｍ／ｍｉｎ（７５Ｗ）时持速给予刺五加制剂１周可使运动时脂肪供能增加１０．２％，心率下降１０．３％，每搏摄氧量增加９．８％；而仅一次给予刺五加制剂组仅仅脂肪供能增加６．８％，其他指标没有改变这说明持续给试样优于仅仅一次给试样的结果。乳酸、心率和无氧阈的结果提示刺五加制剂无论对递增负荷运动还是持续恒定负荷运动人体，均能提高摄氧能力、节省肌糖元，从而发挥抗疲劳作用     

Variations in Psychomotor Efficiency during Prolonged Stay at High Altitude

Alterations in psychomotor efficiency of 25 young adults (age range 21-30 yr) were studied during their stay up to two yr at an altitude of 4000 m. Psychomotor performance, its speed and accuracy were measured by administering an eye-hand coordination test at sea level and altitude after stay periods of 1, 10, 13, 18 and 24 months. Overall psychomotor efficiency, its accuracy and speed declined during early stages of altitude exposure. A progressive recovery was registered in overall performance by way of improvement in accuracy after 13 months presumably due to acclimatization. Speed in performance showed no such gradual return to sea-level standard.     

Effect of wearing personal protective clothing and self-contained breathing apparatus on heart rate,temperature and oxygen consumption during stepping exercise and live fire training exercises

Fire fighter breathing apparatus instructors (BAIs) must possess the ability to respond to both the extrinsic stress of a high temperature environment and the intrinsic stress from wearing personal protective equipment (PPE) and self-contained breathing apparatus (SCBA), repeatedly and regularly, whilst training recruits in live fire training exercises (LFTEs). There are few previous investigations on BAIs in hot environments such as LFTEs, since the main research focus has been on regular fire fighters undertaking exercises in temperate or fire conditions at a moderate to high exercise intensity. In this study, the intrinsic cardiovascular stress effects of wearing PPE + SCBA were first investigated using a step test whilst wearing gym kit (control), weighted gym kit (a rucksack weighted to the equivalent of PPE + SCBA) and full PPE + SCBA (weight plus the effects of protective clothing). The extrinsic effects of the very hot environment were investigated in BIAs in LFTEs compared to mock fire training exercises (MFTEs), where the fire was not ignited. There was an increase in heart rate due to the modest workload imposed on the BAIs through carrying out the MFTEs (25.0 (18.7)%) compared to resting. However, when exposed to fire during the LFTEs, heat storage appears to be significant as the heart rate increased by up to 39.8 (±20.1)% over that of the mock LFTEs at temperate conditions. Thus, being able to dissipate heat from the PPE is particularly important in reducing the cardiovascular responses for BAIs during LFTEs.     

The effects of music tempo and loudness level on treadmill exercise

This study examined the effects of loudness and tempo of background music on exercise performance. A total of 30 volunteers performed five 10-min exercise sessions on a treadmill. The music listened to whilst exercising was either fast/loud, fast/quiet, slow/loud, slow/quiet or absent. Measures of running speed, heart rate, perceived exertion and affect were taken. Significant effects and interactions were found for running speed and heart rate across the different music tempo and loudness levels. More positive affect was observed during the music condition in comparison to the ‘no music’ condition. No significant differences for perceived exertion were found across conditions. These results confirm that fast, loud music might be played to enhance optimal exercising, and show how loudness and tempo interact.     

The impact of various rehydration volumes for firefighters wearing protective clothing in warm environments

This study examined different fluid replacement quantities during intermittent work while wearing firefighting protective clothing and self-contained breathing apparatus in the heat (35°C, 50% relative humidity). Twelve firefighters walked at 4.5 km per h with 0% elevation on an intermittent work (50 min) and rest (30 min) schedule until they reached a rectal temperature of 39.5°C during work periods and 40.0°C during rest, heart rates of 95% of maximum and/or exhaustion. During the heat-stress trials subjects received one of four fluid replacement quantities, high (H), moderate (M), low (L), and no hydration (NH), where H, M and L represented 78%, 63% and 37% of fluid loss, respectively. The total tolerance time (work + rest) was significantly greater during H (111.8 ± 3.5), M (112.9 ± 5.2) and L (104.2 ± 5.8) compared to NH (95.3 ± 3.8). In addition, work time (min), which excluded rest periods, was significantly greater in H (82.6 ± 3.5), and M (82.9 ± 5.2) compared to NH (65.3 ± 3.8). It is concluded that incorporating even partial fluid replacement strategies while wearing firefighting protective clothing and self-contained breathing apparatus in the heat improves tolerance time.     

Promoting children's physical activity in primary school: an intervention study using playground markings

The physical activity levels of 47, 5- to 7-year-old children were assessed before and after a school playground was painted with fluorescent markings. Children‘s physical activity was measured using heart rate telemetry during three playtimes before and after the markings were laid down. Children in the experimental and control groups spent 27 and 29 min, respectively, in moderate to vigorous physical activity (MVPA) before the intervention, increasing to 45 and 36 min, respectively, during the intervention period. MVPA, vigorous physical activity (VPA) and mean heart rate remained relatively stable in the control group compared to respective increases of 10 and 5% of playtime and 6 beats min ^{- 1} in the experimental group during the intervention period. The ANCOVA analysis revealed significant interactions and main effects for the intervention for MVPA, VPA and mean heart rate. Conversely there were no main effect differences between groups. These results suggest that while playground markings had a significant and positive influence on children's physical activity, factors other than playground markings may also influence children's physically active play.     

The effects of hyperoxia on performance during simulated firefighting work

This study evaluated the effects of hyperoxia (inspired oxygen fraction=40%) on performance during a simulated firefighting work circuit (SFWC) consisting of five events. On separate days, 17 subjects completed at least three orientation trials followed by two experimental trials while breathing either normoxic (NOX) and hyperoxic (HOX) gas mixtures that were randomly assigned in double-blind, cross-over design. Previously, ventilatory threshold (Tvent) and VO₂max had been determined during graded exercise (GXT) on a cycle ergometer. Lactate concentration in venous blood was assessed at exactly 5 min after both the experimental trials and after the GXT. Total time to complete the SFWC was decreased by 4% (p< 0.05) with HOX. No differences were observed in individual event times early in the circuit, however HOX resulted in a 12% improvement (p< 0.05) on the final event. A significantly decreased rating of perceived exertion (RPE) was also recorded immediately prior to the final event. No differences were observed in mean heart rate or post-exercise blood lactate when comparing NOX to HOX. Heart rates during the SFWC (both conditions) were higher than HR at Tvent, but lower than HR at VO₂max (p< 0.05). Post-SFWC lactate values were higher (p< 0.05) than post-VO₂max. These results demonstrate that hyperoxia provided a small but significant increase in performance during short duration, high intensity simulated firefighting work.     

Cardiorespiratory and efficiency responses during arm and leg exercises with spontaneously chosen crank and pedal rates

The aim of this study was to compare the cardiorespiratory and efficiency responses between upper (T_UBE) and lower (T_LBE) body exercises at the same relative power outputs and with spontaneously chosen crank (SCCR) or pedal (SCPR) rates. Twelve participants performed exercise bouts set at 20, 40, 60 and 80% of maximal power (MP) separated by passive recovery periods. Oxygen uptake, ventilation, gross and work efficiencies during T_LBE were significantly (P < 0.05) higher than during T_UBE. These results suggest that these responses were not directly related to the relative intensities. However, no significant difference was found for delta efficiency and heart rate values. During T_UBE and T_LBE, gross efficiency increased significantly (P < of MP for T_UBE and T_LBE and the same SCCR and SCPR could explain these results. The present results confirm that the cardiorespiratory and efficiency responses between arm and leg exercises are not always similar, although the power output are normalized in relation to MP and add to the understanding of differences between upper and lower body.     

Blackboard平台在《企业行为模拟—沙盘推演与ERP应用》课程中的应用

本文概括了跨专业实验课程《企业行为模拟——沙盘推演与ERP应用》的特点,并介绍了blackboard平台在该课程教学中的应用,包括提供了个性化学习的内容支持、团队协作学习支持、信息发布的支持、师生交流支持等各方面的内容。     

Accurate work-rate measurements during in vivo MRS studies of exercising human quadriceps

INTRODUCTION: Given that we have reached a point in the field of muscle energetics where absolute measurements are warranted to take the area forward, we designed an ergometer, including two force and two displacement transducers, allowing dynamic and isometric knee extension within a MR system and accurate measurements of power output. METHODS: On the basis of repeated measurements, the force and displacement transducers accuracy was 1% for values ranging from 0 to 394 N and 4% for values ranging from 0 to 20 cm. In addition, measurements were not affected by magnetic field. MRS experiments in exercising muscle were conducted in eight subjects. They performed two standardized dynamic alternate leg extension exercises (25 and 35% of MVC) while the corresponding metabolic changes were measured using (31)P-MRS. RESULTS: The mean power output produced during both exercises were 63 +/- 16 and 81 +/- 15 W while the eccentric work was reduced i.e. 12 +/- 14 and 21 +/- 6 W for the moderate and heavy exercise respectively. The corresponding metabolic changes were significant with a 20-40% PCr depletion and an end of exercise pH ranging from 0.02 to 0.70 pH units. CONCLUSION: Overall, the present ergometer allows quadriceps exercise in a MR system and should be useful for future metabolic studies for which reliable and absolute quantification of power output is warranted.