從動力系統觀點探討多肢段技能學習過程中的熱身減低現象

Multi-segmental motor skill in warm-up decrement

由於傳統上大多以持續性的行為改變來界定運動學習，一些學習過程中的短暫行為改變在觀察學習或發展時，經常被忽略或以平均的方式來處理。目的：本研究旨在以動力系統理論來探討熱身減低這一個在練習階段初期的短暫行為改變。方法：四名參與者練習站在踩板車上向前走的技能，每回合練習50次，共練習7回合。在練習過程中蒐集全身關節和踩板（共15個標記點）的三維空間座標資料，求出連續兩回合間的全身動作空間位移的差值，透過這些差值來計算熱身減低值並作成學習曲線來進行分析。結果：44.4％的熱身減低現象符合指數函數行為，四名參與者中有三名參與者的熱身減低值隨著技能增進而降低，與每日最佳表現的曲線相比較，由指數函數所描述的熱身減低階段有比較大的進步率。結論：在多肢段技能學習過程中所呈現的熱身減低現象存在指數函數行為，支持動力系統理論的假設。而系統所呈現的多時間刻度也顯示出各子系統的演進過程中，於練習初期出現其他像歇後突進現象等短暫的行為改變。Owing to the definition that persistent changes characterize motor learning, the transitory changes during learning are usually been ignored or averaged out in the measurement of learning or development (Newell, et. al, 2001). Purpose: In this study, we investigated the transitory change of warm-up decrement (WU) at the beginning of practice session based on the perspective of dynamical system. Method: Four participants practiced pedalo locomotion skill for seven sessions within fifty trials a session. The difference of whole body movement (15 markers on the joints and the pedals) in three dimensions between consecutive trials was calculated as the value of WU and plotted as the learning curves for analysis. Results: The result showed that 44.4% of the WU demonstrated the behavior of exponential function. The values of WU were found decreased in three participants. Compared with the best performance curves, the rate of WU curves were larger. Conclusion: The existence of exponential function in WU during the process of learning multi-segments skill supported the hypothesis of dynamical system theory. The appearance of multi-time scales implied that there might be other transitory changes such as reminiscence in the early practice during the evolution of subsystems.