【作者】 王欢；

【导师】 江崇民；

【作者基本信息】 上海体育学院 ， 运动人体科学， 2013， 博士

【摘要】 1.研究背景与目的步行作为一项深受大众喜爱的运动，关于它的科学研究由来已久，虽然在能量代谢领域国外的研究已经取得一些成果，但仍有很多问题需要进一步探索。并且，随着测量技术的进步和大众科学健身需求的高涨，给步行的科学研究提出了新的命题。目前，我国关于中国人步行能耗的研究开展较少，缺少基础的研究数据指导科学健身。因此，本研究的主要目的在于测量研究中国人的步行能耗特征，建立场地步行的能耗预测公式，构建有科学证据支持的步行指导建议，探讨步行能耗参数在实际健身指导活动中的应用。2.研究方法研究方法分为两类。一是基础性研究。研究对象为20～60岁健康男女共计1283名，在场地上进行从4.8km/h到8.8km/h多级速度的步行和跑步测试，用“气体代谢”测量仪（Cortex MetaMax3B）采集能耗数据。另外，从1283名受试者中选取部分受试者进行从3.8km/h到6.4km/h的步行能耗测试同时采集步频参数。还有部分受试者为进行能源物质利用研究，开展了3项测试——恒定速度持续运动的能耗测试、自选舒适步速与步频测量、恒定速度改变步频的步行能耗测试。二是应用性研究。用随机控制实验法（RCT）在社区开展了8周步行干预实验，研究对象为50～60岁社区老年人40名，分成三组：对照组、每日万步组、快步频+3300步组，比较不同步行锻炼指导建议对社区老年人步行行为和健康的影响。3.研究结果3.1速度与能耗以及能耗预测公式的建立本研究分析了身高、体重、性别、年龄因素对能耗的影响，研究结果表明，体重是影响能耗最主要因素，性别间存在一定的能耗差异，在预测能耗值时上述因素应考虑在内。4.8km/h～6.4km/h的速度范围内，随着速度增加，步行能耗逐步增加。在建立速度能耗预测公式时，比较了三种模型（线性模型、二次方程模型和指数模型）的拟合效果，结果表明指数模型最佳。［Y1.9e（0.2speed）0.095weight0.0004weight24.52G14.72G0（R2=0.922）］。说明步行速度与能耗之间尽管存在相关关系，但这种相关关系不是线性关系，而是曲线关系（更准确说是指数函数关系）。反映了随着行走速度的加快，人体需要额外的能量带动四肢和躯干，耗能效率降低。此外，本研究发现，国外步行预测公式估测出的步行能耗值与实际测量值之间有显著差异，步速越快差异越大（超过20%的误差），这也从另一个方面证明建立中国人步行能耗预测方法的必要性。本研究对所建模型进行了回代检验，相对误差在-5%～5%之内，说明模型能够较好的模拟中国成年人的步行能耗。3.2步频与能耗步频也是反映步行负荷特征的一个重要变量。相同速度下，个体之间有不同的步频和步幅，步频快、步幅小者能耗水平高，增加8%的能耗。随着速度增加，步频会越来越快，能耗相应增加。本研究也建立了以步频为主要因子的能耗预测方程，同之前建立的速度能耗预测公式比较，步频公式的拟合度不如速度公式，但由大众使用计算步行能耗时更方便。本研究测量了人们自选舒适步速和步频以及能耗特征，舒适步速是4.0～5.0km/h，舒适步频是104-120步/分钟，该速度下男、女的能耗水平接近，为13ml·kg^-1·min^-1。若改变舒适步频，无论是增加还是减少步频，都会增加能耗水平。3.3步行中的能源物质利用特征本研究探讨了不同步速、步频、步行时间与能源物质利用（糖和脂肪氧化）之间的关系。研究发现，中等速度、长时间的步行有利于动员脂肪，快速步行有利于动员糖。固定速度变化步频时，舒适步频脂肪氧化率最低，增加或者减少步频（±15步）不仅增加能耗，还能增加糖和脂肪氧化率。特别对女性而言，相对于大步幅、低步频的步行，采用小步幅、高步频的方式更有利于减脂。3.4步行锻炼建议的建立与应用在分析场地步行能耗数据基础上，用ROC统计法建立了与中等运动强度和大运动强度相对应的步频临界值，即步频110步/分钟和130步/分钟，男女之间有一定的差异。在此基础上还发展了适合中国人的步行锻炼指导建议——对于一个想通过步行锻炼达到指南要求的成年人，步频保持110步/分钟以上的同时每天至少步行锻炼3300步。如果将每日步行步数转化为里程，大约为2公里。基于科学数据建立的步行建议为指导中国人步行锻炼提供了参考。此外，通过8周的社区步行干预实验，就步行锻炼建议进行了应用和验证。干预实验结果表明，“提高步频每日快走3300步”的步行方案可以有效提高社区老年久坐人群的身体活动量（每日步行量从每日4500步～8300步）和改善一些健康状况（体脂率和舒张压下降），但是没能减少久坐时间。同“每日步行1万步”的传统方案相比，该方案更容易被没有锻炼时间或者没有步行锻炼基础的久坐人群接受，服从性较好。在社区步行干预实验中，计步器结合定期的咨询活动是增加步行活动量的有效手段，可以在今后干预项目中推广应用。4.研究结论随着步行速度增加，步行能耗逐步增加。速度与能耗之间呈现指数函数关系。步频是反映步行负荷特征的一个重要变量。步频与能耗之间有密切的关系。人们自选的舒适步频能耗最低，改变步频可以增加能耗。不同的步速、步频的能源物质利用率有不同。增加步速有助于提高糖的利用率，改变习惯步频有助于增加脂肪利用率。本研究建立的步行能耗的预测公式，可以较准确地计算中国人步行活动中的能耗值；建立的步行锻炼建议，经过实际应用证明有效地提高社区久坐老年人群的身体活动量和改善一些健康状况。更多还原

【Abstract】 Background and ObjectivesWalking, as a favorite sport, has been studied for a long time. Although studieshave yielded some good results but there are still many issues that need furtherexploration. Inspired by the improved measurement technology and the high demandsof scientific exercise, we need to take a new perspective to the study of walking.In China, there are few researches about the “Energy expenditure of walking” tillnow so that the evidence for scientific guideline for walking is limited. In that case,the main objectives for this study are as follows: a. measuring the walking features ofChinese population; b. building a prediction equation for walking energy cost; c.evidence-supported walking recommendations; d. discussion about the application ofwalking parameters in the field of exercise intervention.MethodsThere are two sets of methods. The first one is a kind of basic research method.The sample number is1200, aged20-60(male and female; healthy). The test is takenon a flat ground with the speed from4.8km/h to8.8km/h, which is equal to walkingand running respectively. The data is collected by the gas metabolism instrument(Cortex Metamax3B). On the other hand, another group of1200subjects are tested tocollect their step rate from3.8km/h to6.4km/h. The research on utilization of energyfuel is done among some of the subjects: the continuous walking test for a givenspeed, self-selected preferred speed and step-rate test, and changing SF test whilefixing speed.The other kind of methods is applied research methods. Randomized ControlTrial is used in a community.30People (50-60yrs) are divided into three groups tocompare the changes of walking behaviors and health from different interventionstrategies: a control group, a10,000-steps-per-day group, and a fast-SF+3300stepsgroup.Results1. Characteristics of walking energy expenditure and the establishment of predictionformulaWithin the scope of4.8-6.4km/h, the EE increases as long as the speed is increased.When the equation is built, we compared the fitting degrees of three models (Linearmodel, quadratic model, exponential model). The exponential model has the highestdegree.Y1.9e(0.2speed)0.095weight0.0004weight24.52G14.72G0（R2=0.922）. Itindicates that the relationship between speed and energy is not a linear but rather acurvilinear. The curvilinear reflects the extra energy expenditure when lifting walkingspeed and the lower efficiency of energy consumption. Furthermore, there aresignificant differences between the data measured by our study and the estimationfrom the equations built by foreign researchers. And with the accelerated speed, thedifferences increase. It shows the necessity of building our own prediction method forChinese. In this study, we did the back substitution test (relative deviation:±5%).2. Step frequency and walking advice The step frequency (SF) is also an indicator of walking intensity. The SF is moreconvenient for description of the intensity compared with speed. The step ratecut-points corresponding to activity intensity categories (in terms of MET levels) havebeen set up by this study. It could be useful for recommending appropriate amounts ofwalking exercise to meet PA guidelines for Chinese adults. The findings from thisstudy indicate that Chinese adult should walk at least30minutes with a minimal110step·min–1,or3300steps with the same step rate daily to meet PA guidelines. Therewere slight differences on step-rate threshold and minimal steps between women andmen.3. Utilization of energy substrate for walkingThis study investigated the relationship between different speeds, SF, walkingduration, and utilization of energy substrate (oxidation of carbohydrate and fat).It isfound that long time walking with moderate speed is favorable for fat mobilization,while fast walking is positive to CHO mobilization.The self-selected preferred speed is4.0-5.0km/h, with104-120of preferred SF.When changing SF at a given speed, energy consumption of preferred SF is theminimum. Increasing or decreasing SF (±15) not only increases energy consumptioncan also increase the oxidation rate of CHO and fat.4. The results for application researchThis study discussed the use of the walking E.E. parameters in different intervenefields. The parameters can be applied for calculating walking E.E and building theplan for walking exercise though various forms such as the reference, the predictionequation and the table.Moreover, though the walking intervention for8weeks in a community, the partialresults of this study is applied and tested. The results of the intervention show: thewalking goal of3300steps per day can effectively increase the level of physicalactivity (from4500to8800steps per day) for the sedentary seniors, and improvesome heath indicators(decreasing of fat%and DBP). However, the sedentary timewas not deceased. Compared with the traditional program of10,000steps every day,the program is easier to accept for the sedentary people who have no exercise time orexercise habits before, along with good adherence.In addition, pedometer combination of regular consultation activities are aneffective means to increase walking steps during Community walking intervention,which can be promoted in the future.ConclusionsOn the basis of the “Method of Gound Walking Test under Different Speeds” builtin pilot experiments, the E.E parameters are collected from more than1200people ona flat ground. The walking references and equations for estimation are set up on the basis of those parameters, which can help the people make accurate calculation of theenergy cost and develop a walking plan. Besides, the walking advice for Chinese caneffectively increase the level of Physical Activity and improve the health status ofsedentary seniors. In summary, the results of this study provide a valuable referencefor the scientific guidance to the walking for Chinese.更多还原