地板材質改變對行走於其上的步態穩定性之影響

Abstract

跌倒相關傷害為世界上嚴重而普遍的公眾健康議題，於許多已開發國家亦同，且多發生於室內。然地板材質轉換雖為一普遍存在之現象，但於考量室內跌倒因子時較少被討論。有鑑於此，本研究以生物力學的角度去研究人體動作與平衡控制，並以改善居家環境安全、減少地板材質產生的跌倒事件為目標，量化地板材質轉換（例如：客廳至廚房）時步態之改變，更進一步分析地板材質轉換於步態穩定性上之影響。本試驗包含由三種台灣居家常見之地板材質–光面木頭、粗面磁磚、及塑膠地板，組合成的七種地板情境。並使用一組八台攝影機組成之動作擷取系統和兩塊力板量測受測者行走時的運動學與動力學資料。共有五位年輕健康成人、一位中高齡男性及一位高齡女性受測者參與本研究。每位受測者皆以自身習慣之速度行走於六公尺長之實驗走道上，並完成兩種材質連續（走道皆為同一地板材質，包含：光面木頭、粗面磁磚）及四種材質轉換（走道自一地板材質轉換至另一種地板材質，包含：光面木頭至塑膠地板、塑膠地板至光面木頭、粗面磁磚至塑膠地板、塑膠地板至粗面磁磚）等六種地板情境，每種皆重複二十次試驗。此外，年輕受測者需額外完成二十次乾燥粗面磁磚至清水潑覆粗面磁磚的試驗。實驗結果顯示當行走在高摩擦係數至低摩擦係數之地板材質轉換情形時，會有腳跟觸地角度減小約30％、骨盆於矢狀面之前傾角度峰值減小，及所需摩擦係數峰值約增加5-10％的現象。而年輕與中高齡受測者身體質量中心在額狀面上的偏移量增加顯示其步態於地板材質轉換情形下穩定度較差。上述結果顯示材質轉換相較於材質連續的情況，可能會提高跌倒風險，故建議避免採用地板材質轉換的情況，特別是在高齡者的居住空間中。

Fall related injuries are serious public health issues all over the world, including in many developed countries, and most fall incidents occur at home. However, floor transition is a common yet frequently neglected condition when consider risk factors of falls. In consideration of high incident rates of fall-at-home events, our study aims to examine the effect of floor material change (transition), e.g. from living room to kitchen, on the control of level walking and gait stability, in order to reduce the floor material-induced risks of falls and improve the safety of home environment. We used three commonly-used floor materials at home in Taiwan – plane-wood, rough-ceramic, and polyvinyl chloride (PVC), to construct seven different floor conditions for the experiment. An eight-camera motion capture system and two force platforms were used to obtain kinematics and kinetics during level walking. Five healthy young adults and two older subjects volunteered for this study. All subjects completed 20 walking trials, on a 6-m long walkway at self-selected comfortable speed, each under two consistent condition (i.e. same floor material) – plane-wood and rough-wood floor, and four transition condition (i.e. from one material to another) – plane-wood to PVC, PVC to plane-wood, rough-wood to PVC and PVC to rough-wood floor. The five young participants also completed 20 trials on an additional dry to wet ceramic condition. Our results showed that when subjects walked from one floor to another with slightly lower coefficient of friction (COF), the peak required COF under foot increased 5% to 10%, and the foot angle at heel strike decreased about 30%. Moreover, peak anterior pelvic tilt angle was smaller as compared to those when walking under the consistent condition. The results imply a higher risk of falls during walking in transition than consistent conditions. Furthermore, the larger medial-lateral COM excursion also indicates that subjects had less stable locomotion under transition condition. Therefore, we suggest people avoid or use caution when they walk under transition condition, especially for the living environment of the elderly.