Effects of vibration exposure on intrinsic muscle properties

振动暴露对肌肉内在特性的影响

• 批准号: 69-2010
• 负责人: Nigg, Benno
• 金额: $ 1.75万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=543836
• 关键词: Effects; vibration; exposure; intrinsic; muscle

The functions of skeletal muscles include generating forces, facilitating movements, regulation of joint stiffness, and damping of soft tissue vibrations. While the force generation of muscles in relation to movement and joint stiffness has been extensively investigated, there are still open questions regarding the effect of vibrations on the muscles and the mechanisms that might contribute to muscular vibration damping. In this project we investigate the effects of vibrations on muscle force generation. We expect that the intrinsic muscle property of force depression, which has been observed when a contracting muscle is shortened, plays a role when muscles are exposed to vibrations. We speculate that force depression during vibration exposure might either be observed directly as a reduction of the maximal force that the muscle can produce, or it might be observed indirectly as a change in the recruitment of muscle fibers. We will use a custom built exciter to induce longitudinal vibrations into a group of muscles while contracted at maximum voluntary contraction. Muscle force generation will be quantified. Recruitment of muscle fibers during these experiments will be investigated non-invasively by analyzing the muscular activation patterns and by determining the concentration ratio between oxygenated and de-oxygenated hemoglobin in the muscle tissue. Muscle activation patterns will be measured with surface electromyographic sensors and analyzed using a time and frequency resolving wavelet transformation. The ratio between oxygenated and de-oxygenated hemoglobin concentration will be quantified using near infrared spectroscopy. In addition, blood flow within the muscle tissue will be measured using Doppler ultrasound. Damping of soft tissue vibrations is one of the key mechanisms to reduce joint loading and to prevent injuries due to impact shocks. The vibration dampening function of skeletal muscles is therefore essential when coping with the repetitive impact shocks and related vibrations that the body is exposed to during most forms of locomotion. If force depression proves to play a role in how muscles contract during vibration exposure, then it will also affect how the body copes with impact shocks or vibrations.

骨骼肌的功能包括产生力，促进运动，关节刚度调节以及软组织振动的阻尼。尽管已经广泛研究了与运动和关节刚度有关的肌肉的力产生，但仍有关于振动对肌肉的影响以及可能导致肌肉振动阻尼的机制的影响。在这个项目中，我们研究了振动对肌肉力产生的影响。我们预计，在缩短收缩肌肉时已经观察到的力抑郁症的内在肌肉特性，当肌肉暴露于振动时会发挥作用。我们推测，在振动暴露期间的力抑郁症可以直接观察到肌肉可以产生的最大力量的减少，或者可以间接观察到肌肉纤维募集的变化。我们将使用定制的激发仪将纵向振动诱导成一组肌肉，同时以最大的自愿收缩收缩。肌肉力的产生将被量化。这些实验期间肌肉纤维的募集将通过分析肌肉激活模式并确定肌肉组织中含氧和去氧的血红蛋白之间的浓度比，从而无创研究。肌肉激活模式将通过表面肌电图传感器进行测量，并使用时间和频率解决小波转换进行分析。使用近红外光谱法量化了氧化和去氧血红蛋白浓度之间的比率。另外，将使用多普勒超声测量肌肉组织内的血流。 软组织振动的阻尼是减少关节载荷并防止因冲击引起的伤害的关键机制之一。因此，骨骼肌的振动抑制功能在应对重复的冲击冲击和相关的振动时至关重要，而相关的振动在大多数形式的运动中都暴露于身体。如果力抑制在振动暴露期间的肌肉收缩如何收缩中发挥作用，那么它也将影响身体如何应对冲击冲击或振动。