Andersen J L, Klitgaard H, Saltin B
August Krogh Institute, University of Copenhagen, Denmark.
Acta Physiol Scand. 1994 Jun;151(2):135-42. doi: 10.1111/j.1748-1716.1994.tb09730.x.
The myosin heavy chain (MHC) composition of single fibres from m. vastus lateralis of a group of male sprint athletes (n = 6) was analysed, before and after a three months period of intensive strength- and interval-training, using a sensitive gel electrophoretic technique. Significant improvements were observed after training in almost all of a series of performance tests. After training the sprinters revealed a decrease in fibres containing only MHC isoform I (52.0 +/- 3.0% vs. 41.2 +/- 4.7% (mean +/- SE) (P < 0.05)) and an increase in the amount of fibres containing only MHC isoform IIA (34.7 +/- 6.1% vs. 52.3 +/- 3.6% (P < 0.05)). Fibres showing co-existence of MHC isoforms IIA and IIB decreased with training (12.9 +/- 5.0% vs. 5.1 +/- 3.1% (P < 0.05)). Only one out of 1000 fibres analysed contained only MHC isoform IIB. In contrast, a higher amount of type IIB fibres (18.8 +/- 3.6% vs. 10.5 +/- 3.9%, (P < 0.05)) was observed with myofibrillar ATPase histochemistry. The majority of histochemically determined type IIB fibres of sprinters seems therefore to contain both MHC isoforms IIA and IIB. Sprint-training appears to induce an increased expression of MHC isoform IIA in skeletal muscles. This seems related to a bi-directional transformation from both MHC isoforms I and IIB towards MHC isoform IIA.
采用灵敏的凝胶电泳技术，对一组男性短跑运动员（n = 6）股外侧肌单纤维的肌球蛋白重链（MHC）组成进行了分析，分析时间为三个月强化力量和间歇训练前后。训练后，在几乎所有系列的性能测试中均观察到显著改善。训练后，短跑运动员中仅含MHC同工型I的纤维减少（52.0 +/- 3.0% 对 41.2 +/- 4.7%（平均值 +/- 标准误）（P < 0.05）），仅含MHC同工型IIA的纤维数量增加（34.7 +/- 6.1% 对 52.3 +/- 3.6%（P < 0.05））。显示MHC同工型IIA和IIB共存的纤维随训练减少（12.9 +/- 5.0% 对 5.1 +/- 3.1%（P < 0.05））。在分析的1000根纤维中，只有1根仅含MHC同工型IIB。相比之下，用肌原纤维ATP酶组织化学观察到IIB型纤维数量更多（18.8 +/- 3.6% 对 10.5 +/- 3.9%，（P < 0.05））。因此，短跑运动员经组织化学测定的大多数IIB型纤维似乎同时含有MHC同工型IIA和IIB。短跑训练似乎能诱导骨骼肌中MHC同工型IIA表达增加。这似乎与从MHC同工型I和IIB向MHC同工型IIA的双向转变有关。
