壓電肌肉感應貼布分析方法開發及其在肌肉疲勞行為監測之應用

Abstract

本論文旨在開發壓電肌肉感應貼布在量測肌肉疲勞行為時的分析方法，壓電肌肉感應貼布屬一應變感測器，量測肌肉收縮與舒張時造成肌束周長變化連帶造成皮膚表面產生之形變。壓電肌肉感應貼布內部感測材料為聚(偏氯乙烯-三氯乙烯)，此高分子壓電聚合物具有良好的力電耦合特性，本研究使用靜電紡絲製程製作出具壓電絲線，絲線是由奈微米結構的纖維排列形成，其具備可撓性及壓電效應。當肌肉收縮施力造成壓電肌肉感應貼布中的壓電絲線受到來自皮膚表面不同程度的張力時，絲線將所受到之變形會轉成電訊號輸出。本研究進行人體試驗，依受試者能力分群探討不同肌力大小受試者之疲勞差異。實驗中以肌電訊號做為肌肉疲勞之參考指標來與肌肉感應貼布做對照，從肌肉疲勞與肌肉震顫的相關性來得知肌肉實際表現與疲勞機制。經實驗電刺激之平均激活量與平均肌肉收縮變化量兩者為高度相關，相關係數達0.9896，證明了肌電訊號與肌肉感應貼布在時域上的相似特徵。在肌肉疲勞實驗中驗證肌肉感應貼布可直接量測到肌肉疲勞資訊，其時域訊號平均振幅會上升，頻域上則會在高頻8Hz至12Hz之間產生一個額外的峰值，肌肉震顫強度會上升而肌肉震顫頻率則會下降，複合肌電訊號量測結果，從所開發之分析方法亦發現在肌肉疲勞時，肌力較大之受試者發生震顫之強度會小於肌力較小的受試者，且肌肉震顫上升幅度也較小，肌肉震顫頻率則在肌力較小的受試者中呈現微幅遞減情形，而肌力較大的受試者在屈指淺肌及肱二頭肌中隨肌肉負荷量遞增而震顫頻率上升，整體較無呈現頻率下降之趨勢，可能原因為每人使用肌肉習慣的不同，造成快縮肌與慢縮肌比例不同，交換施力的程度也不同，影響快縮肌及慢縮肌的使用比例，造成肌肉震顫頻率出現上升趨勢。實驗結果也顯示非慣用手疲勞現象會較慣用手明顯，非慣用手中的疲勞人數比例增加快速，肌肉震顫強度提升幅度大且震顫行為更強烈，由於天生肌力的差異，隨肌肉負荷愈大時慣用手與非慣用手之震顫頻率皆呈下降趨勢，肌纖維傳遞速率的改變是影響震顫頻率的主因。此研究實際驗證壓電肌肉感應貼布具有監測肌肉疲勞行為之能力並具有極高之可靠度，將可作為運動員技巧提升之個人化穿戴裝置。

The aim of this study is to develop an analysis method to use a piezoelectric muscle patch sensor (MPS) to monitor muscle fatigue. The MPS is a type of strain sensor. It measures the circumference change of a muscle during muscle contractions. It uses electrospun P(VEF-TrFE) piezoelectric fiber bundle to measure the mechanical strain induced by muscle activities. It is a wearable device with an excellent flexibility, which can convert mechanical strain to electrical signal. To verify the performance of the MPS, human studies are conducted to understand the behaviors of muscle fatigue of subject with different levels of muscle strength. The EMG is also used to monitor muscle activities and is used as the reference signal. Experimental results demonstrate that the mean absolute value of electrical EMG stimulation and the average of integrated MPS are highly correlated, the r value is 0.9896, and similar characteristics profiles of the time domain signals were observed. It is also verified that MPS can directly measure muscle fatigue. The average amplitude of the MPS increases under a higher fatigue level, and additional peaks occur between 8Hz and 12Hz. The muscle tremor intensity increases along with a decreasing of the tremor frequency. The tremor frequency of muscle shows a slight decrease in the subjects with smaller muscle strength, while the subjects with greater muscle strength show an increasing trend in the flexor superficialis and biceps brachii. The overall frequency does not show a downward trend. The possible reason is that every person has different muscles usage habits, resulting in different ratios of fast-twitch muscle and slow-twitch muscle and in an upward trend in the frequency of muscle tremors. Lastly, the experimental results show that the fatigue phenomenon of non-dominant hands occurs earlier than that of dominant hands. The proportion of fatigued people in the non-dominant hand increases rapidly, the muscle tremor intensity increases greatly, and the tremor behavior is more intense. The tremor frequency of the dominant hand and the non-dominant hand both shift to lower frequency. It suggests that the change of the muscle fiber transmission rate was the main factor affecting the tremor frequency. In summary, the performance of the MPS is verified, and it can be applied to monitor muscle fatigue. It can potentially be applied as a wearable device for athlete self-trainig.