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Internal fluid pressure influences muscle contractile force.
Proceedings of the National Academy of Sciences of the United States of America ( IF 11.1 ) Pub Date : 2020-01-21 , DOI: 10.1073/pnas.1914433117
David A Sleboda 1 , Thomas J Roberts 2
Affiliation  

Fluid fills intracellular, extracellular, and capillary spaces within muscle. During normal physiological activity, intramuscular fluid pressures develop as muscle exerts a portion of its developed force internally. These pressures, typically ranging between 10 and 250 mmHg, are rarely considered in mechanical models of muscle but have the potential to affect performance by influencing force and work produced during contraction. Here, we test a model of muscle structure in which intramuscular pressure directly influences contractile force. Using a pneumatic cuff, we pressurize muscle midcontraction at 260 mmHg and report the effect on isometric force. Pressurization reduced isometric force at short muscle lengths (e.g., -11.87% of P0 at 0.9 L0), increased force at long lengths (e.g., +3.08% of P0 at 1.25 L0), but had no effect at intermediate muscle lengths ∼1.1-1.15 L0 This variable response to pressurization was qualitatively mimicked by simple physical models of muscle morphology that displayed negative, positive, or neutral responses to pressurization depending on the orientation of reinforcing fibers representing extracellular matrix collagen. These findings show that pressurization can have immediate, significant effects on muscle contractile force and suggest that forces transmitted to the extracellular matrix via pressurized fluid may be important, but largely unacknowledged, determinants of muscle performance in vivo.

中文翻译:

内部流体压力会影响肌肉的收缩力。

液体填充肌肉内的细胞内,细胞外和毛细血管空间。在正常的生理活动中,肌肉内部向肌肉施加一部分已发展的力量,从而形成肌肉内的压力。这些压力通常在10到250 mmHg之间,在肌肉的机械模型中很少考虑到,但是有可能通过影响收缩过程中产生的力和功来影响性能。在这里,我们测试了一种肌肉结构模型,其中肌肉内压力直接影响收缩力。使用气动袖带,我们以260 mmHg的压力对肌肉进行中间收缩,并报告其对等轴测力的影响。加压减小了短肌肉长度(例如,在0.9 L0时P0的-11.87%)的等距力,增加了长肌肉长度(例如1.25 L0时在P0的+ 3.08%)的等距力,但对中间肌肉长度约1.1-1.15 L0无效。通过简单的肌肉形态物理模型定性地模拟了对加压的这种可变反应,该物理模型对加压产生了负,正或中性反应,具体取决于代表细胞外基质胶原的增强纤维的方向。这些发现表明,加压可以对肌肉的收缩力产生直接,显着的影响,并表明通过加压液传递至细胞外基质的力可能是重要的,但在很大程度上尚未得到人们的认可,它是体内肌肉性能的决定因素。取决于代表细胞外基质胶原的增强纤维的取向,对加压的反应是中性还是中性。这些发现表明,加压可以对肌肉的收缩力产生直接,显着的影响,并表明通过加压液传递至细胞外基质的力可能是重要的,但在很大程度上尚未得到人们的认可,它是体内肌肉性能的决定因素。取决于代表细胞外基质胶原的增强纤维的取向,对加压的反应是中性还是中性。这些发现表明,加压可以对肌肉的收缩力产生直接,显着的影响,并表明通过加压液传递至细胞外基质的力可能是重要的,但在很大程度上尚未得到人们的认可,它是体内肌肉性能的决定因素。
更新日期:2020-01-21
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