正常成人行走的生理耗能指數

Physiological Cost Index of Walking for Normal Adults

目的：常用來量測能量消耗的方法是測量耗氧量。此法可得到準確的數據，但需貴重、精密的儀器，並不適用於一般臨床。近來有學者提出另一種量測能量消耗的方法，即測量生理耗能指數(Physiological Cost Index，簡稱PCI)。PCI值是由運動時心跳扣除休息時心跳，再除以行走速度得之。PCI值容易測量，不需貴重儀器且不受情緒、健康狀況、用藥、疾病及環境溫度影響，適用於一般臨床。本研究的目的是建立正常成人的平均PCI值，並找出PCI值與性別、體重及腳長的相關性。方法：46名(男23名，女23名)沒有心肺、神經及骨骼方面疾病的正常成人參與本實驗。首先受測者先填寫一份有關年齡、性別、身高、體重及健康狀況的問卷，並於現場由施測者量測腳長，接著施測者使用心跳速率監測器(Heart Rate Monitor)來測量受測者休息時的心跳，之後再讓受測者在跑步機上行走(跑步機的速度由慢至快共有10種不同的速度)並紀錄10種行走速度時的心跳速率。然後用Student t tests 與Pearson's Correlation Coefficient Tests分析收集的資料。結果：1.所有受測者平均最省能的行走速度是64.37公尺/分鐘。在此速度下，男生、女生及所有受測者的平均PCI值分別是0.4、0.49及0.44心跳次數/公尺。2.在慢速時，PCI值高(較耗能) ﹔當速度增加時，PCI值會下降(較省能) ﹔在高速下，PCI值會再度升高(更耗能)。3.在任何速度下，女生的PCI總是高於男生，且在某些速度下，男生與女生的PCI值在統計上有顯著的差距。4.在高速下，體重與PCI及腳長與PCI(不論男女)都有中等的負相關性。結論：本研究1.建立了正常成人的平均PCI值，此參考值可做為判斷行走是否有困難的指標。2.找出了PCI值與性別、體重及腳長的相關性。

Purpose: The traditional parameter of measuring energy expenditure has been the oxygen uptake. However， this method is cumbersome and the instrumentation may not be available in most clinics. MacGregor (1979) developed the Physiological Cost Index for measuring the energy expenditure of walking. The Physiological Cost Index was defined as the difference of walking heart rate and resting heart rate divided by walking speed. The heart rate is easy to measure in clinics because there is no heavy equipment required and no inf luence comes from emotional stress， fitness， medication， illness， and ambient temperature. The purpose of this study was to establish mean PCI values of walking in normal adults as well as to analyze the relationship between the PCI values and anthropometric parameters such as gender， body weight， and leg length. Method: Forty six healthy subjects (23 males and 23 females) participated in this study. All subjects with past history of cardiopulmonary， neurological or musculoskeletal diseases that could affect walking economy were excluded. A consent form was read and signed by the subjects before the initiation of the study. Information regarding the subject's age， sex， height， weight， medical history and current medical status were obtained by a questionnaire. Leg length was measured from greater trochanter to lateral malleolus. For each subject， heart rates were measured at rest and walking at 10 different speeds on the treadmill with a heart rate monitor. Student t tests and Pearson's Correlation Coefficient Tests were used to analyze the data. Result: 1 The average of the most economical walking speed was 64.37 m/min for males， females， and all subjects with the mean PCI values 0.40， 0.49， and 0.44 beats/m respectively. 2 At slower speeds， the PCI values were high， indicating poor economy. The PCI values decreased to maximum economy as walking speeds increased. At faster speeds， the PCI values were elevated， indicating poor economy. 3 The female subjects had higher PCI values than the male subjects at each walking speed. 4 At higher speeds， there are moderate negative relationships between weight and the PCI values as well as between leg length and the PCI values. Conclusion: 1 In this study， we develop mean PCI values of treadmill walking in adults. The graph of walking PCI in normal adults can be used to compare with that in adults with ambulation disabilities. 2 We found a relationship between the PCI values and gender， body weight， and leg length.