最大等速離心運動引起肌肉損傷對速度發展率的影響

Effects of rate of velocity development following the maximal eccentric exercise-induced muscle damage

目的：探討最大離心運動引起肌肉損傷（eccentric exercise-induced muscle damage，EIMD）對快與慢速度向心收縮之速度發展率（rate of velocity development，RVD）下降率以及恢復速度之影響。方法：10名健康大學男性學生非慣用手肘屈肌群做1回合5組x6次最大等速（30°／s）離心收縮（maximal eccentric exercise，MAX），並在MAX前、後第0－4天各做1次：上臂圍（circumference，CIR）、肘關節活動角度（range of motion，ROM）、酸痛、最大等速向心肌力（30°／s＝MVC－30，300°／s＝MVC－300）及RVD（30°／s＝RVD－30，300°／s＝RVD－300）測驗。結果：一、在MAX後出現明顯肌肉酸痛、ROM下降及CIR增加，這些指標在MAX後第4天仍未恢復至前測水準（p＜.05）。二、在MAX後第0天會使MVC－30及MVC－300出現顯著下降，但在MAX後第4天僅MVC－300恢復至前測值。三、在MAX後第0天會使RVD－30及RVD－300出現顯著下降，RVD－30在MAX後第1天就已恢復至前測水準，但RVD－300在MAX後第4天仍未恢復至前水準（p＜.05），且RVD－300下降的恢復時間也明顯比RVD－30來得長（p＜.05）。結論：在EIMD後的RVD－300恢復速度比RVD－30慢，但MVC－300恢復速度卻比MVC－30快之現象。這可能與向心肌力測驗產生的力量大小與肌纖維受到召募或神經受到活化程度有關。後續研究可針對EIMD引起RVD及MVC不同恢復速度之機制做探討。Purpose: This study tested the hypothesis that the recovery of fast rate of velocity development (RVD; 300°/s, RVD-300) following maximal eccentric exercise-induced muscle damage (EIMD) of the elbow flexors would be slower than that of slow RVD (30°/s, RVD-30). Methods: Ten untrained young men performed 5 sets of 6 maximal eccentric exercises (MAX; 30°/s) of the elbow flexors of the non-dominant arm. Muscle soreness, upper arm circumference (CIR), range of motion (ROM), maximal isokinetic concentric strength at slow (30°/s, MVC-30) and fast (300°/s, MVC-300) angular velocities, and RVD-30 and RVD-300 were measured before to 4 consecutive days after MAX. Results: 1) Development of DOMS, increases in CIR, and decreases in ROM were observed following MAX (p < .05), but these markers had not returned to baseline at 4 days after MAX (p < .05). 2) Immediately after MAX, MVC-30 and MVC-300 decreased significantly, and only MVC-300 had returned to baseline at 4 days after MAX (p > .05). 3) RVD-30 and RVD-300 significantly decreased immediately after MAX, only RVD-30 had returned to baseline at 1 day after MAX (p > .05) while RVD-300 did not return to baseline at 4 days after MAX (p < .05). The recovery of RVD-300 following MAX was slower than that of RVD-30 (p < .05). Conclusions: These results demonstrated that the recovery of RVD-300 following MAX was slower than that of RVD-30, while recovery of MVC-300 after MAX was faster than that of MVC-30. These discrepancies could possibly be related to the extent of the force produced by the concentric strength test and the level of muscle fiber recruitment (nerve activation). Future studies are needed to investigate the mechanisms behind the different recovery rates of MVC and RVD following MAX.