Early resistance training-induced increases in muscle cross-sectional area are concomitant with edema-induced muscle swelling
Early resistance training-induced increases in muscle cross-sectional area are concomitant with edema-induced muscle swelling
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DOI：
10.1007/s00421-015-3243-4
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发表时间：
2016-01-01
影响因子：
3
通讯作者：
Ugrinowitsch, Carlos
中科院分区：
文献类型：
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作者：
Damas, Felipe;Phillips, Stuart M.;Ugrinowitsch, Carlos
已有研究表明，阻力训练(RT)引起的骨骼肌肥大迹象比以往认为的要早得多(类似于3-4周的RT)。我们分析了10名未受过训练的年轻人在放疗开始(T1)、放疗第3周(T2)和放疗结束(T3)时的股外侧肌超声CSA图像及其各自的回声强度(CSA-USecho)，以确定放疗期间早期的CSA是否伴随水肿性肌肉肿胀，从而不完全归因于肥大。功能参数[训练量(Tv=负荷x代表x组)和最大自主收缩(MVC)]和肌肉损伤标志物(肌红蛋白和白介素6)在T2(接近2.7%)和T3(接近10.4%)时较T1显著增加。同样，CsA-USecho在T2(类似于17.2%)和T3(类似于13.7%)时升高。然而，当CsA-USecho被归一化为肌肉CsA的增加时，只有T2显示出显著高于T1的USecho。此外，与T1相比，T2和T3时TV增加，但MVC仅在T3时增加。肌红蛋白和白介素6在T2时较T1时升高，而肌红蛋白在T2时较T3时升高。我们认为，在未经训练的年轻人中，早期RT诱导的肌肉CSA增加并不是纯粹的肥大，因为伴随而来的可能是肌肉损伤导致的肌肉肿胀，这可能是增加的很大比例。因此，肌肉CSA增加(特别是在RT计划的早期)不应被标记为肥大，而不应伴随一些肌肉浮肿/损伤的测量。
It has been proposed that skeletal muscle shows signs of resistance training (RT)-induced muscle hypertrophy much earlier (i.e., similar to 3-4 weeks of RT) than previously thought. We determined if early increases in whole muscle cross-sectional area (CSA) during a period of RT were concomitant with edematous muscle swelling and thus not completely attributable to hypertrophy.We analyzed vastus lateralis muscle ultrasound CSA images and their respective echo intensities (CSA-USecho) at the beginning (T1), in the 3rd week of RT (T2) and at the end (T3) of a 10-week RT period in ten untrained young men. Functional parameters [training volume (TV = load x reps x sets) and maximal voluntary contraction (MVC)] and muscle damage markers (myoglobin and interleukin-6) were also assessed.Muscle CSA increased significantly at T2 (similar to 2.7 %) and T3 (similar to 10.4 %) versus T1. Similarly, CSA-USecho increasedat T2 (similar to 17.2 %) and T3 (similar to 13.7 %). However, when CSA-USecho was normalized to the increase in muscle CSA, only T2 showed a significantly higher USecho versus T1. Additionally, TV increased at T2 and T3 versus T1, but MVC increased only at T3. Myoglobin and Interleukin-6 were elevated at T2 versus T1, and myoglobin was also higher at T2 versus T3.We propose that early RT-induced increases in muscle CSA in untrained young individuals are not purely hypertrophy, since there is concomitant edema-induced muscle swelling, probably due to muscle damage, which may account for a large proportion of the increase. Therefore, muscle CSA increases (particularly early in an RT program) should not be labeled as hypertrophy without some concomitant measure of muscle edema/damage.