Muscle viscosity as a protective mechanism for absorbing mechanical shock

描述（申请人提供）：肌肉在时间和空间上重新分配机械冲击能量并卸载骨骼关节的能力在体育活动中至关重要，例如跑和跳，踢足球，摔跤等。在这些活动中发生的冲击可能超过关节之间的软骨垫所能容忍的水平，软骨垫可以缓冲步行等日常活动带来的适度冲击。我们假设，外部冲击的机械能耗散以吸收机械冲击是骨骼肌的基本功能，骨骼肌的黏度是一个可变参数，可以通过改变收缩肌的张力来自主控制。我们进一步假设，在生物进化过程中，肌肉吸收冲击的能力已经发展起来，使生命能够从海洋到陆地，从水动力环境到空气动力环境，肌肉骨骼系统的负载条件也发生了巨大的变化。到目前为止，还没有可用的实用工具来评估肌肉的动态粘度。我们建议开发一种紧凑、易于使用的体内骨骼肌粘弹性评估仪器，用于探索肌肉减少外部冲击对骨骼和关节的有害影响的机制和能力。该装置将基于使用声辐射力脉冲在组织中产生局部位移，并使用基于相互关联的方法在松弛期间跟踪所产生的位移。该项目的目标包括在肌肉幻影上对开发的设备进行试验台测试，并在有限的运动员群体中进行初步的试点研究，以证明拟议技术的可行性。在体内获得的实验数据将与肌肉粘度分子机制的数学模型的理论预测进行比较。肌肉黏度的定量评价可以为医学生物力学和运动医学的许多问题提供指导。可以通过定量评估肌肉粘弹性的装置评估的肌肉疾病列表包括肌肉营养不良，运动神经元疾病，炎症和代谢性肌病等等。监测肌肉粘度有助于预测关节疾病，如肌腱炎、滑囊炎和骨关节炎，并降低骨质疏松性骨折的可能性。该装置的潜在应用领域包括一般临床应用；康复和职业医学；运动医学：运动员肌肉状态和表现的评估老年学：评估衰老过程中肌肉的变化，特别是在骨质疏松症和骨关节炎期间肌肉骨骼系统的全面衰弱，以及对预防效果的评估。

DESCRIPTION (provided by applicant): The ability of muscle to redistribute the energy of mechanical shock in time and space and unload skeletal joints is of key importance in physical activities, such as running and jumping, playing soccer, wrestling, etc. The impacts that occur during such activities may exceed the level that can be tolerated by cartilage pads between joints which cushion the moderate impacts accompanying mundane activities such as walking. We hypothesize that dissipation of mechanical energy of external impacts to absorb mechanical shock is a fundamental function of skeletal muscle and the viscosity of the skeletal muscle is a variable parameter which can be voluntarily controlled by changing the tension of the contracting muscle. We further hypothesize that an ability of muscle to absorb shock had been developed in the course of biological evolution, allowing the life to move from the ocean to land, from hydrodynamic to aerodynamic environment with dramatically different loading conditions for musculoskeletal system. To date there are no available practical tools for assessment of muscle dynamic viscosity. We propose to develop a compact and easy-to-use instrument for assessment of viscoelastic properties of skeletal muscle in vivo that can be used in exploring the mechanism and the ability of muscle in reducing the harmful effect of external impacts on bones and joints. The device will be based on the use of an acoustic radiation force impulse to generate localized displacements in tissue and the resulting displacements will be tracked during relaxation using cross-correlation based methods. The goals of this project include bench-testing of the developed device on muscle phantoms and conducting preliminary pilot study on a limited group of athletes demonstrating feasibility of the proposed technology. Experimental data obtained in vivo will be compared with theoretical predictions of the mathematical model for the molecular mechanism of the muscle viscosity. Quantitative assessment of muscle viscosity may shed light to many problems of medical biomechanics and sports medicine. The list of muscle disorders that can be assessed by a device for quantitative assessment of muscle viscoelasticity includes muscle dystrophy, motor neuron diseases, inflammatory and metabolic myopathies and many more. Monitoring muscle viscosity could help in anticipating joint diseases, such as tendonitis, bursitis and osteoarthritis and decreasing the probability of osteoporotic bone fracture. The fields of potential applications of such device include general clinical applications; rehabilitation and occupational medicine; sports medicine: assessment of muscle condition and performance in athletes; gerontology: assessment of muscle changes in aging, particularly following total weakening of musculoskeletal system during osteoporosis and osteoarthritis, and estimation of the prophylactics efficacy.