上臂固定休息對肌力、肌肉萎縮與本體感覺的影響

Effect of arm immobilization on impairment of muscle strength, atrophy and proprioception

緒論：選手參加比賽及進行平日運動訓練過程中，發生運動傷害時有所聞。小則挫、擦傷，重則扭、拉傷，甚至出現骨折，往往採用固定（immobilization, IM）休息限制其關節動作、提供支撐並保護受傷組織，防止受傷部位在癒合過程中因外力或移動造成二次傷害。然而，固定對於肌肉功能與本體感覺的影響為何，目前尚不清楚。目的：針對人體非慣用側肘關節進行三週石膏固定休息，探討三週固定對肌力、肌肉萎縮與本體感覺的影響程度。方法：招募18位健康成年年輕男子為研究對象，隨機分配至IM組與對照控制組（non-IM組；n＝9／組）。IM組將其非慣用側肘關節，使用石膏固定完全休息三週；non-IM組則不接受石膏固定。在固定介入前、後，每位研究對象完成單側最大等長肌力（MVC）、上臂圍（CIR）、肌肉厚度（MT）、關節位置覺（PS）、關節釋放反應角度（JRA）等測驗。結果：三週固定導致IM組的MVC（-21.7％）、CIR（-2.3％）、MT（-6.2％）顯著下降（p＜.05），PS誤差變化率（peakPS：6.2％）與JRA改變率（peakJRA：2.6％）顯著上升且明顯大於non-IM組（MVC：1.9％；CIR：0.5％；MT：1.9％；peakPS：3.7％；peakJRA：1.3％）（p＜.05）。此外，MVC、CIR與MT之改變率和PS及JRA呈顯著負相關（p＜.05）。結論：經過三週固定後，肌力與肌肉質量流失間接導致本體感覺失調、關節位置覺與反應能力下降。此結果與測驗方法可供後續相關研究之參考，也可供未來臨床復健治療時之應用。

Introduction: When athletes participate in competitions and during the course of daily training, sports injuries including minor contusions and abrasions, severe sprains, strains, and even fractures frequently occur. As a practice, immobilization (IM) is often used to restrict joint movement, provide support and protect injured tissues, thus preventing the injured part from moving due to external forces during the healing process, and avoiding a secondary injury. However, the effect of IM on the impairment of muscle function and proprioception is still largely unknown. Purpose: The purpose of the present study was to investigate the effects of impairment of muscle strength, muscle atrophy, and proprioception after three weeks of arm immobilization. Methods: Eighteen healthy adult young men were recruited as participants, and then randomly assigned into the IM group or the control group (non-IM group; n = 9/group). Participants in the IM group had their non-dominant elbow joints fixed with a cast and immobilized for three consecutive weeks, while those in the non-IM group did not receive a cast. Before and after the IM intervention, maximal voluntary isometric contraction strength (MVC), upper arm circumference (CIR), muscle thickness of the B-mode ultrasound images (MT), joint position perception (PS), and joint release reaction angle (JRA) of the non-dominant arm of each participant in both the IM and non-IM groups were measured. Results: Significant (p < .05) greater decreases in MVC (-21.7%), CIR (-2.3%) and MT (-6.2%), and increases in PS (peakPS: 6.2%) and JRA (peakJRA: 2.6%) after 3-week of IM than that of the non-IM group (MVC: 1.9%; CIR: 0.5%; MT: 1.9%; peakPS: 3.7%; peakJRA: 1.3%). Moreover, the normalized change in MVC, MT and CIR was significantly correlated with PS and JRA after the 3-week IM (p < .05) period. Conclusion: The results suggested that three weeks of arm immobilization can result in significant muscle strength loss, muscle atrophy, and impairment of proprioception. Thus, these findings may be used as a reference for related follow-up research, and can also be used for future clinical rehabilitation treatment.