Strength and endurance characteristics of the normal human genioglossus.
Strength and endurance characteristics of the normal human genioglossus.
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正常人颏舌肌的力量和耐力特征。
DOI：
10.1164/ajrccm/148.1.179
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Edelman,NH
中科院分区：
文献类型：
--
作者：
Scardella,AT;Krawciw,N;Petrozzino,JJ;Co,MA;Santiago,TV;Edelman,NH
由于颧舌肌的活动在睡眠期间维持上呼吸道通畅起主要作用，其力量和耐力特征具有潜在的重要性。这项研究的目的有两个方面。首先，确定正常人颧舌肌的力量和耐力特征。其次，我们假设，因为颧舌肌中有很高比例的快速糖酵解肌肉纤维，短暂的活动增加会使它更容易疲劳。在五名正常男性受试者中，通过使用换能器测量最大前力(FMAX)来评估舌力。然后在每个受试者中测试100%、80%和50%Fmax时的舌头耐力。为测试短期内颧舌活动增加对其耐力的影响，将轻度高碳酸血症的吸气阻力负荷给予上呼吸道10min，然后重复80%Fmax的膝舌耐力。在另一天，还测试了吸气负荷加高碳酸血症对胸部吸气肌肉耐力的影响。结果表明，平均Fmax为1,267±125(扫描电子显微镜)g，耐力时间(Tlim)在50%、80%和100%的Fmax试验中呈递减趋势。短期激活膝舌肌可使Tlimat的Fmax减少80%，降至加载前的51.4±4.8%(p<；0.05)。然而，吸气肌肉的收缩没有受到影响。我们的结论是，和其他骨骼肌一样，膝舌肌的耐力随着收缩力量的增加而降低。此外，由于短期的活动不足以疲劳胸腔吸气肌，颧舌肌的耐力显著降低。
Since activity of the genioglossus muscle plays a primary role in maintaining upper airway patency during sleep, its strength and endurance characteristics are of potential importance. The purpose of this study was 2-fold. First, to define the strength and endurance characteristics of the normal human genioglossus. Second, we hypothesized that because the genioglossus has a high proportion of fast glycolytic muscle fibers, brief periods of increased activity would make it more susceptible to fatigue. In five normal male subjects strength of the tongue was evaluated by measuring maximal anterior force using a transducer (Fmax). In each subject tongue endurance was then tested at 100%, 80%, and 50% Fmax. To test the effect of a short-term increase in genioglossal activity on its endurance, an inspiratory flow-resistive load with mild hypercapnia was presented to the upper airway for 10 min, after which genioglossal endurance at 80% Fmaxwas repeated. On a separate day the effect of inspiratory loading plus hypercapnia on thoracic inspiratory muscle endurance was also tested. Our results showed that mean Fmaxwas 1,267 ± 125 (SEM) g. Endurance time (Tlim) decreased progressively during 50%, 80% and 100% Fmaxtrials. Short-term activation of the genioglossus caused a reduction in Tlimat 80% Fmaxto 51.4 ± 4.8% of its value before loading (p < 0.05). Tlimfor the inspiratory muscles, however, was unaffected. We conclude that, like other skeletal muscles, genioglossal endurance is reduced as the force of contraction increases. In addition, genioglossal endurance is significantly reduced by short-term activation insufficient to fatigue the thoracic inspiratory muscles.