Gender differences in resistance-training-induced myofiber hypertrophy among older adults.
Gender differences in resistance-training-induced myofiber hypertrophy among older adults.
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老年人阻力训练引起的肌纤维肥大的性别差异。
DOI：
10.1093/gerona/58.2.b108
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Hunter,GaryR
中科院分区：
文献类型：
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作者：
Bamman,MarcasM;Hill,VernishiaJ;Adams,GregoryR;Haddad,Fadia;Wetzstein,CarlaJ;Gower,BarbaraA;Ahmed,Ali;Hunter,GaryR
我们检验了这样一个假设，即在每周3天的膝关节伸肌训练中，以65-80%的最大重复次数进行26周后，老年男性（n= 9，69 ± 2岁）比老年女性（n= 5，66 ± 1岁）经历更大的阻力训练诱导的肌纤维肥大。分析股外侧肌活检的肌纤维面积、肌球蛋白重链亚型分布以及胰岛素样生长因子1（IGF-1）、IGFR 1和肌细胞生成素的mRNA水平。性别×训练交互作用（p<0.05）表明，与女性相比，男性所有三种主要纤维类型（I，IIa，IIx）的肌纤维肥大更大，并且一次重复最大力量增益增强（p<0.05）。血清IGF-1，硫酸脱氢表雄酮，或每个肌肉mRNA的协变并没有否定这些相互作用。在两种性别中，IIx型肌纤维面积分布和IIx型肌球蛋白重链分布减少，同时IIa型肌纤维面积分布增加（p<0.05）。总之，老年人中负荷诱导的肌纤维肥大的性别差异不能用循环IGF-1或硫酸脱氢表雄酮水平或肌源性转录本的表达来解释。
We tested the hypothesis that older men (n= 9, 69 ± 2 years) would experience greater resistance-training-induced myofiber hypertrophy than older women (n= 5, 66 ± 1 years) following knee extensor training 3 days per week at 65–80% of one-repetition maximum for 26 weeks. Vastus lateralis biopsies were analyzed for myofiber areas, myosin heavy chain isoform distribution, and levels of mRNA for insulin-like growth factor 1 (IGF-1), IGFR1, and myogenin. Gender × Training interactions (p<.05) indicate greater myofiber hypertrophy for all three primary fiber types (I, IIa, IIx) and enhanced one-repetition maximum strength gain in men compared with women (p<.05). Covarying for serum IGF-1, dehydroepiandrosterone sulfate, or each muscle mRNA did not negate these interactions. In both genders, type IIx myofiber area distribution and myosin heavy chain type IIx distribution decreased with a concomitant increase in type IIa myofiber area distribution (p<.05). In summary, gender differences in load-induced myofiber hypertrophy among older adults cannot be explained by levels of circulating IGF-1 or dehydroepiandrosterone sulfate, or by expression of the myogenic transcripts examined.