髕骨肌腱機械特性改變中肌腱微循環之效應

Abstract

肌腱為承受力量之結締組織，其機械特性影響運動表現，且肌腱微循環和病變與修補相關。肌腱微循環同時受肌腱內血管之機械性質與代謝物質所調控，此兩參數在運動中對於肌腱血液循環的影響目前尚不明瞭。近年來，因近紅外光譜分析儀（near-infrared spectroscopy, NIRS）技術之進步，使運動狀態下的肌腱微循環能以此非侵入方式量測。但目前仍無研究利用相關技術探討經過運動使肌腱機械特性下降後，肌腱微循環的相對應變化。本研究預計徵召二十位健康的男性大專院校運動員與一般大學生，並依其運動訓練習慣分配為兩組別，分別接受四組四十下或四組八十下之等速離心運動。受試者需進行兩次，分別收取髕骨肌腱機械特性與微循環，並利用表面肌電圖以監測離心運動中是否產生疲勞。參數包括：肌腱剛性、總血紅素、氧飽和度、方均根肌電圖、中位頻率、壓痛閾值。 設計：橫斷式研究。實驗對象：健康男性大專運動員與一般大學生。方法：受試者分為兩組，兩次實驗間隔一週，分別進行機械特性或微循環量測。參數包含離心運動前、後之髕骨肌腱剛性、肌電圖參數與壓痛閾值，離心運動當中則觀察微循環參數之總血紅素與氧飽和度之平均值與斜率。統計分析：使用雙變數重複量測變異數分析。結果：離心運動後兩組肌腱剛性均顯著下降（-17%, p=0.024與-29%, p=0.037）。運動員族群之總血紅素平均值在力量上升階段、力量下降階段顯著高於非運動員族群；運動員之氧飽和度平均值在力量上升階段顯著高於非運動員；而非運動員之氧飽和度斜率在力量下降階段顯著高於運動員。肌電圖參數與壓痛閾值無顯著變化。結論：離心運動使肌腱機械特性下降的過程中，可使肌腱微循環參數改變，此現象在不同訓練程度的健康年輕男性中均可被觀察到。 關鍵字：離心收縮、肌腱機械特性、肌腱微循環、近紅外光譜分析儀、紅光雷射

Tendon is an important mechanical transduction structure. Mechanical properties of the tendon affect force transferring to the bone, while the tendon microcirculation involves tendon lesion and repair. Tendon microcirculation is mediated by the mechanical property of vessels and the circulating metabolites. The influence of these two categories of factors on tendon microcirculation during exercise is still unknown. Near-infrared spectroscopy is a noninvasive method for measuring tendon microcirculation in vivo, but currently no study applied this technique to evaluate the acute change of microcirculation during and after an eccentric exercise protocol. Design: Cross-sectional study. Participants: 20 healthy male recreational college-level athletes and college students. Method: The subjects will be randomized assign into 2 groups (4sets of 40 repetitions or 4sets of 80 repetitions of eccentric exercise). Two measurements (mechanical properties or microcirculation) will be performed for each subject in a one-week interval. Variables including patellar tendon stiffness, total hemoglobin (THb), oxygen saturation (SO2), RMS EMG, median frequency and pain pressure threshold were measured at baseline, during the exercise, and 3 different time point after the eccentric exercise. Statistics: Two-way repeated measurement ANOVA will be used for data analysis. Significant level is set at 0.05. Results: Tendon stiffness decreased significantly after eccentric exercise in two groups (-17%, p=0.024 and -29%, p=0.037). In athlete group, mean values of THb during force ascending and descending phases were significantly higher than non-athlete group. In addition, mean values of SO2 during force ascending were also significantly higher. In non-athlete group, slope of SO2 during force descending were significantly higher than athlete group. No significant differences were observed in all EMG variables and pain pressure threshold. Conclusions: Eccentric contraction can decrease tendon stiffness. During the exercise, changes of tendon microcirculation in both regular trained or untrained college-level participants were significant.