慣性感測器應用於游泳動作分析之敘述性綜論

Application of Inertial Measurement Unit in Swimming Movement Analysis: A Narrative Review

慣性感測器具有足夠精準度和穩定性，應用於運動項目的實驗，但目前缺乏統整慣性感測器在游泳運動中實際應用的方法。目的：統整慣性感測器在分析游泳運動之應用，同時對過去相關研究進行綜述和討論。結語：感測器取樣頻率需根據奈奎斯特取樣定理，研究建議取樣頻率不應低於15Hz，且安裝位置的影響存在較大差異。濾波設定，巴特沃斯濾波器廣泛應用，游泳動作訊號頻率較為低頻，但截止頻率的選擇仍需靈活調整。泳姿辨識，下背部的加速規訊號常被使用，且訊號穩定性優於手腕。而手腕位置在動作分期與划手次數計量有較好的表現，並顯示出優於傳統影像分析的效能。旋轉矩陣與互補濾波器的使用，顯示感測器在監控游泳者的關節角度上有實用價值，但仍需解決萬向鎖和高速運動時雜訊與訊號飄移問題。過去研究主要於基本動作識別和量測，如今更多研究關注更複雜的動作特徵。未來有望進一步提升角度測量的準確性，更全面了解游泳運動的表現和技術水平。

Inertial Measurement Unit (IMU), known for their precision and stability, are increasingly employed in experimental studies across various sports. However, a comprehensive synthesis of their specific applications in swimming is currently lacking. Purpose: to consolidate the use of IMU in analyzing swimming movements and provides a review and discussion of relevant past research. Methods: A targeted search using specific keywords combining swimming and IMU was conducted on Google Scholar and PubMed (MEDLINE). Swimming-related keywords included (swimming, frontcrawl, freestyle, backstroke, backstroke, breaststroke, butterfly), and IMU-related keywords included (accelerometer, gyroscope, inertial sensors, IMU (Inertial Measurement Unit), MEMS (Micro-Electro-Mechanical Systems), acceleration, angular velocity). Relevant literature and systematic reviews were collected to integrate applications of IMU devices in swimming-related research. Conclusion: The sampling frequency of sensors should adhere to the Nyquist Sampling Theorem, suggest a minimum sampling frequency of 15H. Filtering settings commonly utilize the Butterworth filter, with flexibility required in choosing the cutoff frequency due to the low-frequency nature of swimming motion signals. In terms of swim stroke recognition, the accelerometer signal from the lower back is frequently utilized due to its stability, outperforming the wrist location. The wrist position demonstrates superior performance in motion segmentation and stroke count measurement, surpassing traditional image analysis efficiency. The use of rotation matrices and complementary filters demonstrates the practical value of sensors in monitoring swimmers' joint angles, with challenges to address such as gimbal lock and noise and signal drift during high-speed movements. Previous research primarily focused on basic motion identification and measurement. The current trend is shifting towards exploring more complex motion features. The future holds the potential for further enhancing the accuracy of angle measurements, providing a more comprehensive understanding of swimming performance and technical proficiency.