前言：跑步經濟性 (Running Economy, RE) 是跑步表現的重要指標，在過去多數使用VO2max測試定義RE，而相關生物力學參數及跑步方式已被證明會影響RE，如：觸地時間、步頻、步幅、著地模式等，隨跑步速度改變生物力學參數也會有非線性的改變。其中觸地時間比 (Duty Factor, DF) 是近幾年被高度討論的議題，也經實驗證實與跑步表現、傷害具一定關聯性，但過去實驗仍有多處矛盾之結果，與跑步速度之間關聯性也較不明確。目的：本研究欲探究最大攝氧量跑速之55%、65%、75%、85%四種跑速下，跑步經濟性與生物力學參數之相關性，以及各項參數在不同跑速間差異，找到評估或檢測跑步經濟性的替代指標。方法：本實驗招募12位有從事規律運動之健康男性，先進行最大攝氧量測試，將該測試最大跑速的55%、65%、75%、85%作為第二部分測試強度，以皮爾森積差相關分析攝氧量與生物力學參數相關性，並比較不同速度下各項生理、生物力學參數差異性。結果：RE與DF未達顯著相關 (r= -.18 ,p= 0.23) ，其餘參數與RE相關係數均落在 (r = 0.32~0.64)之間，但在能量消耗與DF之間呈現 (r= -0.52) 中等程度相關。各項生理、生物力學參數不同速度之間均達顯著差異 (p < .05)。結論：在室內跑步機進行攝氧量或RE相關測試時，DF也許較不適合作為評估跑步經濟性的替代性指標，以單一運動學參數評估跑步經濟性較為合適。

Introduction: Running Economy (RE) is a critical indicator of running performance, traditionally defined by VO2max testing. Various biomechanical parameters and running techniques, such as ground contact time, step frequency, stride length, and foot strike pattern, have been shown to influence RE. These biomechanical parameters exhibit nonlinear changes with varying running speeds. The Duty Factor (DF), the ratio of ground contact time to the total stride time, has gained significant attention in recent years. Experimental evidence has demonstrated its association with running performance and injury risk. However, past studies have yielded conflicting results, and the relationship between DF and running speed remains unclear. Purpose: This study aims to investigate the correlation between running economy (RE) and biomechanical parameters at four different running speeds: 55%, 65%, 75%, and 85% of the maximum running speed associated with VO2max. Additionally, the study seeks to identify differences in these parameters across various running speeds to find alternative indicators for evaluating or assessing running economy. Methods: This experiment recruit 12 healthy males with regular exercise habits. Initially, subjects will undergo a VO2max test, and the running speeds corresponding to 55%, 65%, 75%, and 85% of their VO2max will be used as the intensities for the second part of the test. Pearson correlation analysis will be used to examine the relationship between oxygen consumption and biomechanical parameters, and differences in physiological and biomechanical parameters across various speeds will be compared. Results: No significant correlation was found between RE and DF (r= -0.18, p= 0.23). The correlation coefficients between RE and other parameters ranged from (r= 0.32 to 0.64). A moderate correlation was observed between energy expenditure and DF (r= -0.52). Significant differences in physiological and biomechanical parameters were found across different speeds (p<0.05). Conclusion: When conducting VO2max or RE-related tests on a treadmill, DF may not be suitable as an alternative indicator for assessing running economy. Evaluating RE based on a single kinematic parameter is more appropriate.

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