Changes in muscle activity in response to different impact forces affect soft tissue compartment mechanical properties
Changes in muscle activity in response to different impact forces affect soft tissue compartment mechanical properties
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DOI：
10.1115/1.2746384
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发表时间：
2007-08-01
影响因子：
1.7
通讯作者：
Nigg, Benno M.
中科院分区：
文献类型：
--
作者：
Boyer, Katherine A.;Nigg, Benno M.
肌电图（EMG）活动与步行和跑步中落地前的几项任务相关，包括腿部定位、关节僵硬以及可能控制软组织隔室振动。肌肉调谐的概念表明，如果冲击的频率内容接近软组织隔室的固有频率，则肌肉活动模式响应于冲击条件的小变化而变化的一个原因是使软组织隔室振动的幅度最小化。软组织隔室的机械性能部分取决于肌肉激活，因此假设与不同冲击条件相关的肌肉激活模式的变化将导致软组织隔室的加速度传递率的变化。一个钟摆装置被用来系统地管理冲击的脚跟穿鞋男性参与者。墙的反作用力，选定的腿部肌肉，软组织隔室和鞋跟杯加速度的EMG量化为两种不同的冲击条件。对于每个受试者/软组织隔室/鞋组合，确定冲击加速度到软组织隔室的传递率。对于这种受控的影响的情况下，结果表明，在软组织隔间的阻尼特性的变化相关的EMG强度和/或平均频率的相关肌肉的变化，在响应于在冲击界面条件的变化。这些结果提供了支持的肌肉调谐的想法，在肌肉活动的变化，以响应小的变化，在冲击条件的一个原因可能是为了尽量减少振动的软组织隔间，在脚跟罢工开始。
Electromyographic (EMG) activity is associated with several tasks prior to landing in walking and running including positioning the leg, developing joint stiffiness and possibly control of soft tissue compartment vibrations. The concept of muscle tuning suggests one reason for changes in muscle activity pattern in response to small changes in impact conditions, if the frequency content of the impact is close to the natural frequency of the soft tissue compartments, is to minimize the magnitude of soft tissue compartment vibrations. The mechanical properties of the soft tissue compartments depend in part on muscle activations and thus it was hypothesized that changes in the muscle activation pattern associated with different impact conditions would result in a change in the acceleration transmissibility to the soft tissue compartments. A pendulum apparatus was used to systematically administer impacts to the heel of shod male participants. Wall reaction forces, EMG of selected leg muscles, soft tissue compartment and shoe heel cup accelerations were quantified for two different impact conditions. The transmissibility of the impact acceleration to the soft tissue compartments was determined for each subject/soft tissue compartment/shoe combination. For this controlled impact situation it was shown that changes in the damping properties of the soft tissue compartments were related to changes in the EMG intensity and/or mean frequency of related muscles in response to a change in the impact interface conditions. These results provide support for the muscle tuning idea-that one reason for the changes in muscle activity in response to small changes in the impact conditions may be to minimize vibrations of the soft tissue compartments that are initiated at heel-strike.