Department of Biology of Physical Activity, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland.
Scand J Med Sci Sports. 2012 Apr;22(2):240-8. doi: 10.1111/j.1600-0838.2010.01198.x. Epub 2010 Sep 9.
Mammalian target of rapamycin and mitogen-activated protein kinase (MAPK) signaling pathways have been highlighted as important for muscle adaptations and thus, they may distinguish adaptations to different exercises. Typically, resistance exercise designed for muscle hypertrophy has moderate intensity (60-80% of one repetition maximum, 1 RM) while one prioritizing maximal strength with minor hypertrophy has a higher intensity (≥90% of 1 RM). Eight untrained men (28.4 ± 3.7 years) conducted two different bilateral leg press exercise protocols: hypertrophic (5 × 10 RM) and pure maximal strength (15 × 1 RM) in a counterbalanced, cross-over design with 1 week between exercises. Vastus lateralis muscle biopsies were taken before and 0.5 h after resistance exercise, or in six controls (26.5 ± 3.6 years) who rested. The phosphorylation of p70S6K (Thr(421) /Ser(424) ), rpS6 (Ser(240/244) and Ser(235/236) ) and MAPK p38 as increased (∼2-16 fold) after both exercise protocols. However, the phosphorylation of MAPK Erk1/2 and p70S6K at Thr(389) increased only after 5 × 10 RM. The increase in the phosphorylation of p70S6K (Thr(421) /Ser(424) ), rpS6 (Ser(235/236) ) and Erk1/2 were higher after 5 × 10 RM (P<0.05). No changes were seen in controls. In conclusion, MAPK signaling is greater after hypertrophic than maximal strength exercise protocol. This may mediate adaptations specific to these different types of training regimens.
哺乳动物雷帕霉素靶蛋白和丝裂原活化蛋白激酶（MAPK）信号通路已被强调为肌肉适应的重要因素，因此，它们可能区分不同运动的适应。通常，旨在促进肌肉肥大的抗阻运动具有中等强度（60-80%的 1 次重复最大值，1RM），而优先考虑最大力量和轻微肥大的运动则具有较高强度（≥90%的 1RM）。8 名未经训练的男性（28.4 ± 3.7 岁）采用平衡、交叉设计，在两种不同的双侧腿推运动方案中进行实验：肥大（5×10RM）和纯最大力量（15×1RM），两次实验之间间隔 1 周。股外侧肌活检在抗阻运动前和 0.5 h 后进行，或在 6 名对照者（26.5 ± 3.6 岁）中进行，他们只休息。两种运动方案后，p70S6K（Thr（421）/Ser（424））、rpS6（Ser（240/244）和 Ser（235/236））和 MAPK p38 的磷酸化均增加（~2-16 倍）。然而，只有在 5×10RM 后，MAPK Erk1/2 和 p70S6K 的 Thr（389）磷酸化才增加。p70S6K（Thr（421）/Ser（424））、rpS6（Ser（235/236））和 Erk1/2 的磷酸化增加在 5×10RM 后更高（P<0.05）。对照组没有变化。总之，在肥大运动方案后，MAPK 信号比最大力量运动方案更强。这可能介导了这些不同类型的训练方案特有的适应。
