足掌內肌的神經肌肉評估：(1)正常足與柔軟性扁平足的差異；(2)柔軟性扁平足介入三週縮足運動前後的差異

Neuromuscular assessments of foot intrinsic muscles: (1) between individuals with and without flexible flatfoot (2) before and after a 3-week short foot exercise training in individuals with flexible flatfoot

黄資惠(Tzu-Hui Hunag)

指導教授 ： 陳譽仁

國立臺灣大學/醫學院/物理治療學研究所/博士(2019年)

https://doi.org/10.6342/NTU201902953

摘要

背景：柔軟性性扁平足為常見的足部變形，且與許多症狀相關如足部疼痛、不穩定、下背痛及其他下肢問題，進而影響生活品質。根據足核心系統理論，足掌肌肉尤其是外展拇指肌，在支持及動態調節內側縱弓扮演重要的角色。對柔軟性扁平足而言，外展拇指肌長時間及反覆的被動牽拉可能會造成肌肉反射特性的改變，進而影響姿勢表現。雖然過去的文獻顯示足掌肌肉的神經肌肉表現在健康足及柔軟性性扁平足有差異，然而，在不同姿勢下外展拇指肌H反射的差異性還尚未被比較。縮足運動能獨立收縮足掌肌肉群，尤其是外展拇指肌。而過去研究也指出搭配神經肌肉電刺激可促進正確地學習縮足運動。雖然縮足運動已被用來獨立收縮足掌肌肉，但其訓練後的在神經肌肉改變的證據仍有限。目的：(1)探討執行不同姿勢下，外展拇指肌 H 反射及姿勢晃動在正常足及柔軟性扁平足的差異。(2)探討介入三週縮足運動後，柔軟性扁平足執行不同姿勢任務時，外展拇指肌H 反射及姿勢晃動的變化。方法：實驗一共有12位正常足及12位柔軟性扁平足受試者參與。兩組受試者的外展拇指肌 H 反射及姿勢晃動在三種姿勢下進行紀錄包含趴姿、雙腳站姿及單腳站姿。實驗二共有10位柔軟性扁平足參與訓練。三週的縮足運動訓練包含3階段(被動建模、主動協助建模及主動建模)12部分。受試者的外展拇指肌 H 反射及姿勢晃動在訓練前後分別記錄並進行分析比較。統計分析：實驗一以獨立樣本t檢定進行兩組受試者基本資料的比較。外展拇指肌 H 反射及肌電圖相關參數則以二因子混合設計變異數分析進行比較，並以Bonferroni校正進行事後比較。兩組受試者的足底壓力中心位移則使用獨立樣本t檢定來進行比較。實驗二以重複設計變異數分析比較三週縮足運動介入前後，柔軟性扁平足外展拇指肌 H 反射、肌肉電訊號及姿勢晃動的改變。結果：實驗一，在所有姿勢下，柔軟性扁平足的外展拇指肌 H 反射均較正常足低(趴姿：正常足：3.24 ± 1.05，柔軟性扁平足：1.08 ± 0.61；雙腳站姿：正常足：0.906 ± 0.55，柔軟性扁平足：0.442 ± 0.38；單腳站姿：正常足: 0.197 ± 0.18，柔軟性扁平足：0.036 ± 0.012)。在單腳站姿下，柔軟性扁平足外展拇指肌的肌電圖訊號較正常足低(正常足：74.44 ± 10.79%最大自主等長收縮；柔軟性扁平足：130.31 ± 8.41%最大自主等長收縮)。在單腳站姿下，柔軟性扁平足的前－後、左－右足底壓力中心位移較正常足大(P <.05)。實驗二，在三週的縮足運動訓練介入後，柔軟性扁平足的外展拇指肌 H 反射在單腳站姿下有顯著增加(訓練前：0.12 ± 0.03，訓練後：0.19 ± 0.07)。訓練後的外展拇指肌肌電圖訊號在單腳站的姿勢下較訓練前顯著下降(訓練前：114.42 ± 34.76 %最大自主等長收縮，訓練後：78.77 ± 28.04%最大自主等長收縮)。在站姿下，柔軟性扁平足的左－右足底壓力中心位移也較訓練前有顯著減少(P <.05)。結論：柔軟性扁平足受試者可能表現出神經肌肉的適應性，例如降低H反射和增加肌電訊號，以及降低姿勢穩定性。在為期3週的縮足運動訓練之後，具有柔性扁平足的受試者之H反射路徑的興奮性在單腳站下增加。此外，訓練後增加的姿勢穩定性也反映了功能的改善。

關鍵字

柔軟性扁平足 ； 外展拇指肌 ； H 反射 ； 姿勢控制 ； 縮足運動

並列摘要

Background: Flexible flatfoot (FF) is a common foot deformity that can be associated with symptoms such as pain, instability, lower back and lower extremity disorders as well as health-related hazards that directly or indirectly impacting the quality of life. Foot core system theory indicates that plantar intrinsic foot muscles (IFMs) play an important role in supporting and regulating medial longitudinal arch dynamically, especially abductor hallucis muscles (AbH). Prolonged and repeated stretching of AbH in FF may cause changes in muscle reflex properties and further influence postural performance. Although there are some evidences showing neuromuscular differences in IFMs between individuals with and without FF, however, AbH muscle reflex under different postural conditions have never been examined. ‘Short foot exercise’ has been described as a maneuver to isolate the contractions of plantar intrinsic muscles, especially AbH. Previous study also recommended that short foot exercise combined with neuromuscular electrical stimulation is an effective way to learn this exercise. Although short foot exercise could isolate IFMs’ contractions, very limited evidence showed differences in muscle activities and neuromuscular control changes after training. Purposes: (1) to investigate differences in AbH H-reflex and postural sway between individuals with normal foot (NF) alignment and FF under different postural conditions (2) to investigate Changes in reflex of AbH and postural sway during different postural tasks after a 3-week short foot exercises training regimen in individuals with FF. Methods: In the study one, 12 normal foot (NF) and 12 FF individuals were recruited. The AbH H-reflex and CoP displacement were recorded during 3 postural tasks: prone, double-leg stance (DLS), and single-leg stance (SLS) conditions. In the study two, 10 FF individuals were recruited. There were three stages and 12 sections in the short foot exercise training protocol: passive modeling, active-assistive modeling and active modeling. AbH H-reflex and CoP displacement were elevated before and after 3-week short foot exercise to explore the training effects. Statistical analysis: In the study one, the demographic characteristics were compared among the groups by an independent-sample t-tests. A two-way mixed model analysis of variance and Bonferroni corrections was used to compare the AbH H-reflex and EMG related outcomes. An independent-sample t-tests was used to compare CoP displacements between the groups. In the study two, two-way repeated measured analysis of variance was used to compare AbH H-reflex, EMG and CoP displacements before and after a three-week training program under prone, DLS and SLS postural conditions. Results: Study one: Under all postural conditions, AbH H-reflex was significantly lower in the FF group (prone: NF: 3.24 ± 1.05, FF: 1.08 ± 0.61; DLS: NF: 0.906 ± 0.55, FF: 0.442 ± 0.38; SLS: NF: 0.197 ± 0.18, FF: 0.036 ± 0.012). Under the SLS condition, AbH EMG was significantly higher in the FF group (NF: 74.44 ± 10.79% MVIC; FF: 130.31 ± 8.41% MVIC), and CoP displacement for the medial-lateral and anterior-posterior directions were significantly higher in the FF group (P < .05). Study two: There was significantly higher AbH H-reflex ratio under the SLS conditions after the 3-week short foot exercise training interventions ( pre-training: 0.12 ± 0.03, post-training: 0.19 ± 0.07). AbH EMG was significantly lower under the SLS postural conditions after the interventions (pre-training: 114.42 ± 34.76 % MVIC, post-training: 78.77 ± 28.04% MVIC). Significant decreased CoP displacement for the medial-lateral directions under DLS and SLS conditions were observed when compared to pre-training situation. Conclusions: Individuals with FF may exhibit neuromuscular adaptations, such as decreasing H-reflex and increasing EMG, and decreasing postural stability. After the 3-week short foot exercise training, the excitability in the H-reflex pathway increased during the SLS condition in individuals with FF. Furthermore, the increased postural stability after the training also reflected the functional improvement.

並列關鍵字

Flexible flatfoot ； Abductor hallucis muscle ； H- reflex ； Postural control ； Short foot exercise

參考文獻

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