跌倒和肌肉減少症是威脅老年人身體健康和生命安全的兩個重要問題。肌肉減少症所致的肌肉力量減弱和平衡能力下降是導致老年人跌倒的最主要原因。老年人跌倒最普遍和最嚴重的後果是脆性骨折。跌倒所致的脆性骨折是常見老年病，同時也是導致老年人生活品質下降和死亡的最主要原因之一。高頻低幅振動(LMHFV)是一種非侵入性生物物理干預手段，通過給予全身物理震動刺激，可有效提高肌肉功能和改善骨質。由此推測高頻低幅振動治療有望應用於預防跌倒/骨折及延緩肌肉減少。 / 本研究的目的在於，採用臨床隨機對照研究方法，通過對社區老年人進行高頻低幅振動治療，探索高頻低幅振動治療在預防跌倒/骨折、降低骨折發生率以及延緩肌肉量下降的作用。本研究假設高頻低幅振動治療可有效提高肌肉力量和改善骨質，從而降低骨折風險、跌倒率以及骨折發生率。本研究將分成兩部分進行以驗證此假說。 / 第一部分研究中，710名60歲或以上的社區老年人按社區中心為單位隨機分成振動治療組和對照組。振動治療組給予35Hz，0.3g的振動治療，並以每天20分鐘，每週5 天，持續18 個月；對照組則如常生活而不予振動治療。18個月治療過程中，振動治療組的跌倒率低於對照組46% (p=0.001)。同時，治療組的在平衡力測試中的反應時間、移動速度，和最遠移動距離也都有明顯改善 (所有指標 p<0.001）。在高頻低幅振動治療停止一年後，振動治療組的主導腿和非主導腿肌肉力量仍高於接受振動治療前 (p=0.029, p=0.002)。在平衡力測試中，治療組的反應時間、移動速度以及最遠移動距離也明顯優於對照組 (p=0.001，p=0.014，p=0.007)。在停止治療的一年期間，兩組受試者的肌肉力量，平衡能力以及生活品質均有下降的趨勢，但兩組的下降率並無明顯的差異。 / 第二部分的設計是基於第一部分的研究成果，目的在於更深入研究高頻低幅振動治療對肌肉功能、肌肉量以及肌肉質素的影響。60名社區老人隨機分成對照組和振動治療組。振動治療組給予35Hz，0.3g的高頻低幅振動治療，並以每天20分鐘，每週5天，持續9個月; 對照組則如常生活而不予振動治療。9個月後，治療組的主導腿和非主導腿的肌肉力量明顯高於對照組 (p<0.001，p=0.003)。在用以評估肌肉力量以及平衡力的計時起立坐下測試中，振動治療組用以完成連串起立及坐下動作的時間明顯低於對照組 (p=0.009)。振動治療組的下肢功能尺度問卷評估結果也明顯優於對照組 (p=0.002)。雖然兩組間的身體成份及肌電圖測試結果並無明顯差異，但治療組的肌肉量和肌電圖平均頻率均有上升的趨勢。而且，在兩部分實驗中，受試者對高頻低幅振動治療均有良好的耐受性，目前並沒有發現對受試者身體產生不利影響。因此，高頻低幅振動治療可安全地應用於社區老年人。 / 總括而言研究結果證明高頻低幅振動治療可明顯降低老年人跌倒發生率。9至18個月的振動治療可明顯改善老年人下肢功能和平衡力。在完成為期18個月高頻低幅振動治療後的1年，肌肉功能仍高於對照組，表明高頻低幅振動治療具有長期療效。因此，高頻低幅振動治療應在社區推廣作為老年人跌倒的預防方案之一。 / Fall and sarcopenia are two major problems among elderly. Poor muscle strength and balancing ability resulted from sarcopenia are the major causes of fall incidences. Fragility fracture is one of the most common and serious consequences of falls, which accounts for most of the deaths, as well as morbidity and poor quality of life. Low magnitude high frequency vibration (LMHFV) treatment is a non-invasive biophysical modality to provide a whole-body mechanical stimulation, which was previously shown to improve muscle performance and bone quality implying the potential application for fall/fracture prevention and reducing muscle loss. / The objectives of this study were to conduct prospective randomized controlled clinical trials to investigate the effect of LMHFV treatment on fall/fracture prevention, fracture risks and muscle loss among community elderly. It was hypothesized that LMHFV treatment could enhance muscle performance and bone quality, thus reducing the fracture risks, fall incidence and fracture rate. Two parts of studies were designed to testify the hypotheses. / In the Part I study, a total of 710 community elderly who were aged 60 years or above were recruited and randomized into vibration or control group on center-basis. The subjects in vibration group received LMHFV treatment (35Hz, 0.3g) 20min/day and 5days/week for 18 months, while control group remained sedentary. During the 18-month study period, the vibration group had reported 46% lower fall incidence rate when compared with control group (p=0.001). Significant improvements were found in reaction time, movement velocity and maximum excursion of balancing ability assessment, and also the quadriceps muscle strength (p<0.001 to all). After ceasing the LMHFV for 1 year, the muscle strength of dominant and non-dominant legs in vibration group were still significantly better than the baseline assessed before intervention (p=0.029 and 0.002 respectively), as compared with the control. In balancing ability test, the reaction time, movement velocity and maximum excursion of vibration group also remained significantly improved, as compared with the control group (p=0.001, 0.014 and 0.007 respectively). During the 1 year post-intervention period, both groups had shown a decreasing trend of muscle strength, balancing ability and quality of life but the rate of changes were not significantly different between two groups. / With reference to the results of Part I study, the Part II study was designed to investigate further the effects of LMHFV on muscle performance, mass and quality. 60 community elderly were recruited and randomized into either vibration or control group. Vibration group subjects received LMHFV treatment (35Hz, 0.3g) 20min/day, 5days/week for 9 months, while control group remained sedentary. Significant enhancement of dominant and non-dominant leg muscle strength was observed in the vibration group after 9 months LMHFV (p<0.001 and =0.003 respectively). In the chair rising test assessing muscle power and balancing ability, vibration group showed significantly shorter time needed for sit-to-stand cycles than the control (p=0.009). Significant increase of the lower extremity functional scale was also observed in the vibration group (p=0.002). No significant findings were found in the body composition and vibromyography (VMG) assessment, however, a trend of increasing lean mass and VMG mean frequency were observed. Also, minimal adverse effects were documented in both parts of study; all subjects were well-tolerated for LMHFV treatment. LMHFV is therefore safe and applicable to elderly in the community setting. / LMHFV was demonstrated to reduce fall incidences significantly. Significant effects on improving lower limbs function and balancing ability were observed as early as 9 months after treatment. Enhancement of muscle performance still remained significant 1 year after completion of 18-month LMHFV treatment, indicating strong residual effects of LMHFV. Use of LMHFV in the community as an effective fall prevention program is recommended. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Chi Yu. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 154-167). / Abstracts also in Chinese.