三軸加速規用於評估身體活動量的方法與應用

Investigate the method and application of three-axis accelerometer for assessing physical activity

加速規可用於評估身體活動量與運動強度等，然而評估時可能因動作形式的差異，需穿戴至適當的身體部位，且收取之加速度訊號繁雜，若能事先瞭解適當的穿戴位置與收取之數據後判斷、分析的方式，則能提高研究效率。本文彙整過去使用加速規探討身體活動量之相關實證性研究，並提出在何種運動形式下，適當的穿戴位置數據判斷與分析方式，藉此提供相關研究人員，作為後續從事研究之參考依據，以利提升研究效益。經文獻分析後得知，將加速規穿戴至受試者髖關節 (腰部) 為最多，其次為手臂。數據判斷與分析方面，主要可分為，一、直接將運動過程中所產生的加速度閾值進行加總或平均。二、透過動作過程中，產生的加速度閾值與時間軸進行比對。三、事先收取加速度校標，在與實際動作之加速度閾值進行比對。四、以各軸向加速度閾值與合加速度積分值判定。加速規所產生的加速度閾值或時間軸的變化，可順利評估身體活動量、運動強度與競技技術。建議欲釐清生活中身體活動、慢走、徒手肌力運動與游泳運動可將加速規穿戴至受試者髖關節 (腰部)，而籃球與足球等球類運動則可穿戴至慣用側手臂。研究人員可針對研究目的、動作形式與需求，選擇適合該研究之判斷、分析數據的方式與穿戴的位置，藉此提高研究效率。

 

Accelerometer uses to assess physical activity and exercise intensity. However, the assessment accuracy is highly associated with its wearing position. Thus, understanding the relationship between wearing position and signal quality of the accelerometer will shed light on assessing varied physical activities and potential research scenarios. Referring to a substantial amount of previous studies’ empirical data, we propose an effective approach in determining the ideal sensor’s wearing positions for acquiring valid signals for the body movement assessment. The wearable-device sensors are primarily positioned on the hip and secondarily positioned on the upper arm. Four steps are dealing with signal processing. Step 1 is to integrate the averaged acceleration signals at a given period of the physical movement, step 2 is to match the above signals with the time axis, step 3 is to calibrate the signal and set a threshold to analog to start or end of the movement, and step 4 is to evaluate all directional signals. Based on the processed signal, threshold and directional information, investigators can effectively assess the wearer’s physical activity, exercise intensity, and even movement skills. Wearable device positioned in the waist or hip was found to be more effective in the detection of jogging, swimming, and free-weight muscle-strengthening exercise. However, for basketball and football, the assessment would be more effective if the wearable device is positioned on the dominant side’s arm. In summary, the position of the wearable device and signal processing needs to be relatively considered to validly assess physical activities and movement characteristics.