Non invasive measurement of muscle oxygenation in elite athletes in the field

许多生理测量中的一个主要问题是，执行测量的行为本身会改变被观察的系统。科学家面临的挑战是开发能够对生理过程进行非侵入性评估的技术。一种名为近红外光谱(NIRS)的技术以前被用来测量血液的光吸收的波长依赖性，从而测量其含氧量(高氧动脉血呈鲜红色，而耗氧的静脉血呈紫色/蓝色)。原则上，近红外光谱可以测量肌肉的血氧饱和度。肌肉使用氧气来帮助将食物能量(碳水化合物/脂肪)转化为可利用的化学能量，这种化学能量可以驱动肌肉收缩，使运动员能够跑步、骑自行车和游泳。运动会消耗氧气，因此肌肉中的氧气量(其氧饱和度)是衡量正在输送的氧气是否跟上了它的消耗。在有氧运动中有足够的氧气；在无氧运动中则不是这样。在2012年奥运会上夺得金牌已成为英国体育的首要任务。有许多因素将影响英国队在2012年奖牌榜上的位置，包括为精英运动员制定优化的训练制度。制定有效的训练策略需要教练对运动员在跑道边的表现进行实时反馈。目前，缺乏能够为赛场上的优秀运动员提供可靠和准确的生理监测的可用设备。目前，几乎没有可用的方法可以让我们测量运动员在野外训练时的生理变化。从理论上讲，近红外光谱方法可以用来测量训练运动员的肌肉氧合。然而，目前商业化的近红外测定仪体积大、重量重、不可携带。该可行性项目的目的是开发一种非侵入性、电池驱动、紧凑的近红外测定仪，它可以测量局部绝对肌肉血氧饱和度，并通过无线链路将数据实时传输给教练。来自埃塞克斯(以及英国体育)精英运动员和教练的反馈将为设计提供参考，以确保该设备将被所有运动员接受，并且不会影响运动表现。在设计原型设备的同时，我们将测试如何使用新技术来提高运动成绩。我们首先将重点放在跑步和自行车等项目上，在这些项目中，很容易在实验室进行复杂的生化和生理测量(使用呼出的空气的分析和血液样本中的测量)。我们的目标是通过尝试重现体育赛事的测试，详细了解近红外光谱测量在这个实验室环境中的使用。有了这些知识，我们最终将能够在训练精英运动员的过程中将这项技术应用于该领域。在许多可能性中，我们首先将重点放在NIRS的两个用途上，即在短跑项目中优化运动员的热身，以及在耐力项目中设计最佳的配速策略(何时快速和何时保存能量)。除了这项可行性研究之外，我们的长期目标是开发一种能够提供多种生理测量的设备，用于广泛的运动和极端环境，包括游泳和高原训练。虽然我们认为这种设备有可能在2012年给英国体育运动带来优势，但它的制造也将是2012年奥运会后红利的一部分，因为它将在医疗应用中有重大用途，例如帮助截瘫患者改善肌肉功能和调查患者的脑损伤。

A major problem in many physiological measurements is that the act of performing the measurement can itself alter the system that is under observation. The challenge for scientists is to develop techniques which allow the non invasive assessment of physiological processes. A technique called Near Infrared Spectroscopy (NIRS) has previously been used to measure the wavelength dependence of the optical absorption of blood and therefore its oxygen content (highly oxygenated arterial blood is bright red whilst oxygen depleted venous blood appears purple/blue in colour). In principle NIRS allows for the measurement of the oxygen saturation of the muscle. Muscles use oxygen to assist in the conversion of food energy (carbohydrate/fat) into the useable chemical energy that can drive muscle contraction and allow an athlete to run, cycle and swim. Exercise uses up oxygen and therefore how much oxygen is in the muscle (its oxygen saturation) is a measure of whether the oxygen being delivered is keeping up with its consumption. In aerobic exercise there is sufficient oxygen; in anaerobic exercise this is not the case. Achieving gold in the 2012 Olympics has become a top priority for UK Sport. There are many factors that will influence the position of Team GB in the medals table in 2012, including the development of optimised training regimes for elite athletes. Informed development of effective training strategies requires coaches to be given real time feedback on an athlete's performance at the trackside. Currently there is a scarcity of available devices that provide reliable and accurate physiological monitoring of elite athletes in the field. There are currently very few available methods which allow us to measure physiological changes in an athlete while they are training in the field. In theory NIRS methods could be used to measure muscle oxygenation in training athletes. However current commercial NIRS machines are large, heavy and non-portable.The aim of this feasibility project is to develop a non-obtrusive, battery driven, compact, NIRS device that measures local absolute muscle oxygen saturation and transmits this data via a wireless link to the coach in real time. Feedback from elite athletes and coaches at Essex (and via UK sport) will inform the design to ensure that the device will be acceptable to all athletes and will not compromise athletic performance. In parallel with the design of the prototype device we will be testing how the new technology could be used to enhance sports performance. We will focus initially on events, such as running and cycling, where it is easy to make complex biochemical and physiological measurements in the laboratory (using analysis of the exhaled air and measurements in blood samples). Our aim is to understand in detail the use of NIRS measurements in this laboratory setting using tests that attempt to recreate sporting events. Armed with this knowledge we will ultimately be able to apply the technology in the field during the training of an elite athlete. Of many possibilities we will initially focus on two uses for NIRS / optimising warm-up for athletes in sprint events and designing optimal pacing strategies (when to go fast and when to conserve energy) in endurance events. Beyond this feasibility study our long-term aim is to develop a device capable of providing a number of physiological measures for use in a wide range of sports and extreme environments including swimming and altitude training. Whilst we feel this device has the possibility of giving UK sport an edge in 2012, its manufacture will also be part of the Olympic post-2012 dividend, as it will have significant use in medical applications e.g. assisting paraplegics in improving muscle function and in investigating brain injury in patients.