Measuring of skeletal muscles' dynamic properties.

Many studies have been completed to determine how muscles work. One of the aspects to study is the muscle response and how to measure it. The main aim of this study was to build a noninvasive measuring system that would be simple to use and would measure the muscle response as close to the muscle as possible. The measuring method was based on a magnetic displacement sensor measuring the muscle belly response. The sensor was placed adjacent to the skin over the muscle and measured radial movements of the muscle belly. The muscle response to single twitch electrical stimulation was measured. Different skeletal muscles or muscle groups have different biomechanical characteristics. The rise time of the muscle belly response was the characteristic parameter for this study. The comparison of muscles' responses in terms of the values of their normalized rise time parameters confirmed their identities as slow or fast muscles. The value of the normalized rise time parameter of a slow muscle was four times less than the value of the parameter of a fast muscle. Although the question remains as to how the available measuring techniques provide estimation of skeletal muscles' dynamic properties, this proposed measuring method contributes to a better understanding of skeletal muscles' dynamic properties. It offers a possible way of studying the muscle structure from the muscle's response to electrical stimulation in a simple noninvasive way.