座椅位置對自行車踩踏時下肢生物力學的影響

Abstract

擁有騎乘自行車的習慣不僅可以訓練下肢肌肉，亦可以提升肌耐力與心肺功能。自行車也是一項適合老年人和體重過胖者的運動，甚至能幫助有下肢傷害的患者進行復健。然而，不適當的騎乘姿勢仍舊可能造成運動傷害，尤其是膝關節的部分。藉由改變自行車的座椅位置，可以影響下肢運動學和力動學的變數，進而改善不適當的騎乘方式。本篇研究目的即為探討五種不同座椅位置的調整和不同的阻力之下對人體下肢的影響，實驗招募15位受試者進行自行車的騎乘，每個人各自執行15種測試條件。實驗之後續分析主要利用逆向動力學計算下肢生物力學變數，至於統計分析則以重複量測變異數方法比較五種不同座椅位置的影響，主要分析的變數為下肢的關節角度、關節受力和關節力矩。研究結果發現當座椅位置向前、向上和向下調整之後，均會顯著改變膝關節和踝關節的角度。在向下座椅位置之條件下，可以發現膝關節的伸展力矩最大、彎曲力矩最小；於向座椅位置之條件下剛好相反，膝關節的伸展力矩最小、而彎曲力矩最大。

Cycling, which strengthens lower limb muscles, cardiovascular performance and maintenance, is a recommended sport for the elderly, overweight people, and injured patients for rehabilitation. However, improper cycling conditions such as inappropriate cycling posture can increase the risks of knee disorders. Changing the bicycle’s seat position can affect the kinematics and kinetics on the lower limbs. The aim of this study was to compare five seat positions and also three different resistances on the biomechanics of the lower limbs. Fifteen subjects were recruited to perform cycling in 15 conditions in total. Inverse dynamic analysis and statistical analysis were performed. Repeated measure ANOVA was used to test variances within five seat positions. The variables were joint angle, joint forces and joint moments on crank angle 10°, 20°,…, 360° and the peak value. Current results indicated that forward, upward and downward seat positions had significant effects on knee joint angle and ankle joint angle. In downward seat position, the maximum extensor moment of the knee joint was found and also the minimum flexor moment. On the other hand, the minimum extensor moment of the knee joint and the maximum flexor moment were found in backward seat position.