在動作科學這領域,現今研究的方法皆是以外顯的行為表現,來同步觀測腦內的活動情況。在手指動作控制大多為力量上升及力量穩定兩種,少有發現有學者研究力量下降的行為,因此本實驗在設計上訂定兩種力量任務(25%MVC、50%MVC),且這兩種任務皆有三種不同力量階段(上升期、穩定期、下降期)。並且藉由練習的機制來探討,力量下降與練習之間的相互關係。 參與實驗的人員,予以分為實驗組及對照組,實驗組接受為期四週的練習,每週三次每次約一小時共十二次訓練,對照組則不練習。兩組皆在四週的前後各記錄一次腦波數據,觀察這四週的練習及不練習在腦部的差異。實驗結果顯示實驗組在練習之後對於任務的執行有明顯的進步,力量的控制更加準確,因此力量的誤差有顯著的降低,透過統計分析在力量三階段皆有顯著效應,對照組則沒有此結果。兩種任務中,在力量上升期的誤差皆大於下降期的誤差值,推測這是由於上升期的力量變化率高於下降期之變化率,因此在行為的控制上較容易產生誤差。在Cz的電極位置練習後電壓有下降情況產生,以腦波五個時間成分(BP-600~-500ms,MP-100~0ms,MMPramp,MMPstatic,MMPdown)進行統計分析,在練習這因素上具有統計上的意義。說明練習確實會造成大腦皮質活動狀況的改變。由於神經反應的經濟性,在下降期有明顯的雙峰結果產生,觀察上升期及下降期腦波放電的結果,發現在下降期的放電量明顯小於上升期,由於下降期的峰值電位及行為表現誤差皆小於上升期,說明本實驗之設計在力量下降之力量變化率比上升期來的低,此因素確實影響大腦的動作反應及行為表現的誤差。
In the fields of study, all methods were focused on the external behavioral expression and the corresponsive activities in the brain which were mostly regarding on force rising and maintenance during finger coordination. Little studies examined the decreasing of force associated with force production. Therefore, two different levels of force (25%MVC and 50%MVC) were set up as well as three different force phases (ramp, static, down) were applied during force production. Due to the difficulties of force decreasing, this study imposed repetitive practice to explore the relationship between phases of force. 20 collegiate subjects were divided into the experiment group and the contrast group, ten for each group. The experimental group was asked to receive 12 practice sessions for 1 h, 3 days a week for 4 weeks, the contrast group was lack of practice. We recorded two EEG sessions (pre and post) separated by 4 weeks, and observed the difference between the two groups. The results showed that the experimental group revealed obvious progress after practice and the control of force was more accurate. Therefore, the error of force significantly reduced. The ANOVA indicated a significant effect of each force phase, but the contrast group revealed negative outcome. The error of force rising was larger than decreasing of force in both force levels. We suggested that the rate of force development was higher in ramp phase than in down phase thus caused less error in down phase. The amplitude of movement-related cortical potentials (MRCP) at Cz electrode site reduced after practice as well. For the five components of MRCP (BP-600~-500ms, MP-100~0ms, MMPramp, MMPstatic, MMPdown), the ANOVA indicated a significant main effect of sessions after practice. It showed that practice may cause the changes in brain cortical activation. Because of the economical neuron activities after learning, a clear bi-model phenomenon was reveal during the down phase. Examined the results of EEG data in ramp phase and down phase, we found the amplitude of MRCP in down phase was lower than in ramp phase. Due to the rate of force development in down phase was less than ramp phase in this experiment, both the peak values of MRCP and the error of force in down phase were lower than that of ramp phase. It suggested that the rate of force and practice played significant roles and influenced the brain behavior associated with finger force production.