八週矯正型鞋墊介入對低足弓肥胖學童步態表現之影響

Effects of an 8-week orthotics insoles intervention on gait performance in obese children with low-arched foot

緒論：過去研究發現低足弓肥胖學童在步行時需比正常學童承受更多的額外重量，造成下肢負荷增加，肌肉關節等傷害發生的風險變大，且低足弓學童因足部支撐及減震功能不足，亦容易發生跌倒的現象。然而穿著矯正型鞋墊是否能有效改善低足弓肥胖學童步態問題，目前在臨床上仍尚未釐清。故本研究期以縱貫式研究探討低足弓肥胖學童穿著矯正型鞋墊後，分別在第4週及第8週之運動學與動力學等步態參數變化情形，以評估矯正型鞋墊介入之效果。方法：招募近半年內無下肢傷害病史之8名肥胖男性學童，且其足弓需同時符合Clarke`s angle（α≤32o）與Chippaux-Smirak index（α＞0.45）兩種低足弓指數。利用1台高速攝影機（120Hz）及1塊測力板（1200Hz）同步擷取受試者在尚未穿著矯正型鞋墊前之第1週，及穿著矯正型鞋墊後之第4週與第8週步行時慣用腳在支撐期間的運動學及動力學參數，再分別使用Kwon 3D與Dasy Lab 6.0動作分析軟體進行參數處理。參數以重複量數單因子變異數進行統計分析（α＝.05）。結果：介入鞋墊第8週後，會減少踝關節的最大蹠屈角度，並增加其背屈角度。而負荷率與推蹬期垂直力峰值，分別在鞋墊介入第4週與第8週後有顯著的減少。結論：低足弓肥胖學童經過8週矯正型鞋墊介入，其足弓塌陷問題有較完善的支撐，並降低著地力量達到緩衝效用，踝關節也得到較大動作範圍，負荷率與垂直力峰值也有所下降。因此本研究認為透過鞋墊長期的介入能降低低足弓肥胖學童步態行走下肢生物力學傷害的風險。

Introduction: Previous studies have found that obese children with low-arched foot need to sustain more extra weight than normal children during walking. It resulted in increased loading on lower extremity and higher injury risk of joint and muscle. Children with low-arched foot also have insufficient support and shock absorption problems on foot, which may cause higher risk of falling. It is still not clear in the clinic that the effects of orthotics insoles on improving gait performance in obese children with low-arched foot. Therefore, this study used a longitudinal study to investigate the effects of wearing orthotics insoles daily for eight weeks on kinematics and kinetics gait parameters in obese children with low-arched foot. Methods: Eight healthy obese male children with low-arched foot were recruited for this study. The low-arched foot discrimination was followed by Clarke`s angle (α ≤ 32°) and Chippaux-Smirak index (α > 0.45). Each subject wore the orthotics insoles daily for eight weeks. A high-speed camera (120 Hz) and two force plates (1,200 Hz) were used to collect dynamic gait data on the first, fourth and eighth weeks. Kinematic and kinetic parameters were processed by Kwon 3D and Dasy Lab 6.0 motion analysis software respectively. One-way ANOVA with repeated measures was used to compare each parameter among three different week-groups (α = .05). Results: After wearing the orthotics insoles daily for eight weeks, the maximal ankle flexion angle was increased, but the maximal ankle dorsiflexion angle was decreased. Wearing the insoles after four and eight weeks, the loading rate and the second peak of vertical force were significantly decreased. Conclusion: Orthotics insoles could provide better support for the arch collapse problem in obese children by wearing it for eight weeks. It decreased the loading rate and vertical force peak during gait. Therefore, wearing corrective shoe insole for long term could reduce the lower extremity biomechanical injury risk in obese children with low-arched foot during gait.