緒論：離心運動產生的高張力易使肌纖維受到細微損傷，進而使肌肉中蛋白質(如：肌酸激酶，creatine kinase, CK)被釋放到血液循環中。CK常被用做為離心運動引起肌肉損傷(eccentric exercise-induced muscle damage, EIMD)的血液生化評估指標。先前文獻發現離心運動後血液CK會出現個別差異，進而影響EIMD的評估效果，但目前尚未釐清CK與EIMD評估指標(如：肌力)之間的關係。因此本研究目的在於考驗最大等速離心運動(maximal isokinetic eccentric exercise, ECC)引起血液CK個別差異反應和血液CK個別差異是否與EIMD評估指標有關之假設。方法：以200名健康大學男性坐式生活型態為研究對象，統一以非慣用手肘屈肌群，進行一回合5組×6次ECC(30°/s)，並在ECC前、後0～5天各進行一次抽血(分析CK)、最大等長肌力(maximal voluntary isometric contraction strength, MVC)、肘關節活動角度(range of motion, ROM)、上臂圍(circumference, CIR)及肌肉酸痛(muscle soreness, SOR)測驗。接著，將ECC後恢復期全體(all subjects, ALL組；CK: 44～66300 IU/L)CK峰值做高低排序後，選取排序最前與最後20%樣本(n=40/組)，做為高(high responders, HR組；CK ＞ 9251 IU/L)和低反應組(low responders, LR組；CK ＜ 219IU/L)，並以二因子變異數分析及多元逐步迴歸分析，針對所有依變項進行統計分析。結果：一、ALL、HR、LR組在ECC後各評估指標產生的變化皆明顯比前測來得大(p ＜ .05)。二、ALL和HR組在ECC後各指標變化皆明顯大於LR組(p ＜. 05)。三、ALL組CK峰值與MVC(r = -.42)、SOR(r = .43)、ROM(r = -.73)、CIR(r = .65)；HR組CK峰值與SOR(r = .38)、ROM(r = -.63)、CIR(r = .68)等最大變化值有相關(p ＜ .05)。四、ALL組ROM(R^2 = .52)和CIR(R^2 = .57)；HR組CIR(R^2 = .45)和ROM(R^2 = .54)具有預測CK峰值的效果。結論：EIMD時確實會引起高低不同程度之血液CK反應，而且高CK反應者其它EIMD指標也同樣會產生較大程度之反應趨勢。因此，這些研究發現可做為評估EIMD個別差異反應時之參考。

Introduction: The high tension generated by eccentric exercise is likely to cause significant damage to the muscle fibers, which further causes the protein (e.g. creatine kinase, CK) originally located within the muscles to be released into the blood circulation. CK is one of the common blood biochemical markers used to evaluate the magnitude of eccentric exercise-induced muscle damage (EIMD). Previous studies reported elevation of blood CK after eccentric exercise demonstrated huge individual differences, which was liable to affect the evaluative results of EIMD. However, the relationship between CK and other EIMD indices (e.g. muscular strength) following ECC is remained unknown. Therefore, the purpose of the present study is to test the variability in blood CK after maximal isokinetic eccentric exercise (ECC) and the hypothesis that whether variability in blood CK following ECC is relevant with other EIMD indices. Methods: Two hundred college-aged male performed 5 sets of 6 ECC (30°/s) elbow flexors applying the non-dominant arm. Blood CK, maximal voluntary isometric contraction strength (MVC), range of motion (ROM), upper arm circumference (CIR), and muscle soreness (SOR) were taken instantly or within 5 days, both before and after the ECC tests. Afterwards, peak-CK values post-ECC for all subjects were ranked, then selected top and bottom 20% of the whole samples (n = 40/group) as high (HR) and low responders (LR) groups. Data were analyzed by a two-way ANOVA and multiple regression analysis. Results: 1. Compared to the baseline level, significant (p ＜ .05) changes were found in all dependent variables after ECC in ALL subjects, HR and LR groups. 2. The HR group has greater (p ＜ .05) changes in variables than the LR group after ECC tests. 3. Peak CK values in the ALL subjects group had correlation (p ＜ .05) with maximal changes in MVC (r = -.42), ROM (r = -.73), CIR (r = .65) and SOR (r = .43) after ECC; Peak CK values in the HR group had correlation (p ＜ .05) with maximal changes in SOR (r = .38), ROM (r = -.63) and CIR (r = .68) post-ECC. 4. Maximal changes in ROM (R^2 = .52) and CIR (R^2 = .57) for all subjects group, and maximal changes in CIR (R^2 = .45) and ROM (R^2 = .54) for the HR group had the effect of predicting peak CK values. Conclusions: These results showed changes in CK and all EIMD markers post-ECC were higher in HR than LR. Thus, these findings of the present study can be provided as reference for trainees or sport scientists of variability in EIMD for general public.