Bioimpedance Applied on Skeletal Muscle Assessing to Resistance Training Effects
Electrical impedance measurements of biological tissues, termed as bioimpedance, quantify the passive electrical properties of biological tissues including skeletal muscles. Resistance training is important to skeletal muscle in terms of strength gaining, but could introduce fatigue and damage with improper training protocols. For this dissertation, the effect of bicep curl exercise is studied using bioimpedance measurement on localized bicep tissue. Several research tasks are set for this dissertation. Firstly, the accuracy and limitations of impedance measurements with Keysight E4990A impedance analyzer under high residual impedance were studied, with OSL compensation, tetrapolar configuration and 10 kHz to 100 kHz recommended for bioimpedance measurement for maximum accuracy. Secondly, localized bioimpedance was used to assess the changes of bicep tissue of healthy young adults participating in isotonic exercise designed to induce skeletal muscle fatigue with significant changes of pre- and post-exercise impedances observed, caused by the change of muscle property. Next, bioimpedance experiment was further performed on bicep tissue of healthy young adults participating and recovering from eccentric bicep curls exercise with significant change of impedance observed 72 and 96 hours post-exercise, different from isotonic experiment result in terms of recovery time potentially due to the delayed-onset feature of eccentric exercise. Lastly, the use of an equivalent electrical circuit, the Cole-impedance model, to represent bicep tissue bioimpedance was evaluated by fitting the data collected from isotonic and eccentric exercises. Significant changes in Cole impedance parameters, Rinf, R1 and C were observed in isotonic eccentric exercise, proposed to be related to muscle swelling and architecture alteration, respectively. Conclusions and contributions of the current study were shown at the end, as well as limitations and future improvements.