本研究目的是以Gibson(1979/1986)所提出之環境賦使(affordances)概念，檢驗個體在知覺不受限制情況下，如何覺知與外界環境之關係，探討髖關節柔軟度對覺知跨越溝渠距離的影響。以16名女大學生為實驗參加者，區分成柔軟度優(n=8)與柔軟度差(n=8)兩組，過程中讓實驗參加者判斷最大與適宜跨步距離兩種情況，共40次，並量測實際跨步距離與人體測量學參數。統計分析使用2（柔軟度）×2（任務情況：知覺與實際跨步距離）×2（動作能力：最大與適宜距離）的混合設計的三因子變異數分析，後兩個因子為重覆。所得結果：交互作用皆未達顯著水準，知覺距離與實際跨步距離沒有顯著差異，顯示個體可覺知其跨越距離，個體與外界環境存在著相互對應的關係，並可以直接覺知其關係，導引動作的產生；柔軟度因子顯著，柔軟度優者（平均數85.01cm）比差者（平均數74.74cm）實際跨越並知覺較遠距離；動作能力因子達顯著，表示在個體的最大與適宜距離有明顯的不同。Pearson相關係數顯示知覺最大跨步距離與左髖曲屈活動度之相關顯著。本研究結論是由研究結果得知個體可以覺知與環境間的關係（最大與適宜跨步距離），並能區辨兩種動作能力的不同，且在知覺最大跨步距離時，柔軟度與知覺距離有關。

The present study used the theory of affordance (Gibson, 1979/1986) to investigate the perception of individuals' affordances for gap cross ability when they were unrestricted, and the effect of hip flexibility on perceiving the distance of gap-crossing. Sixteen female undergraduate students (aged 19-23 years) with good hip flexibility (n=8) and with poor hip flexibility (n=8) were voluntarily participated in this study. All the subjects were required to judge their maximal and optimal crossing distances, and then their actual maximal and optimal crossing distance and anthropometric parameters were measured. The collected data were analyzed by mixed design three-way ANOVA (Flexibility factor × Task condition × Motion ability). The two-way and three-way interactions were not significant in this study. The Flexibility effect was significant which indicates the perceived and actual distance of the good flexibility group (mean=85.01 cm) were farther than that of the poor flexibility group (mean=74.74 cm). The Task condition was not significant, indicating that the perceived and actual distances were not distinguishable. However the Motion ability was significant which means the maximal crossing distance and the optimal crossing distance was different. Furthermore, Pearson product-moment correlation showed that the perceived maximal crossing distance significantly related with the left hip joint flexion. From this data we concluded that the perception of maximal crossing distance related to hip flexibility. People are able to differentiate two different abilities and perceive the relations between themselves and the environment.