Tilp Markus, Steib Simon, Schappacher-Tilp Gudrun, Herzog Walter
Human Performance Laboratory, University of Calgary, AB, Canada, and the Institute of Sports Science, Karl-Franzens-University Graz, Graz, Austria.
J Appl Biomech. 2011 Feb;27(1):64-73. doi: 10.1123/jab.27.1.64.
Force enhancement following muscle stretching and force depression following muscle shortening are well-accepted properties of skeletal muscle contraction. However, the factors contributing to force enhancement/depression remain a matter of debate. In addition to factors on the fiber or sarcomere level, fiber length and angle of pennation affect the force during voluntary isometric contractions in whole muscles. Therefore, we hypothesized that differences in fiber lengths and angles of pennation between force-enhanced/depressed and reference states may contribute to force enhancement/depression during voluntary contractions. The purpose of this study was to test this hypothesis. Twelve subjects participated in this study, and force enhancement/depression was measured in human tibialis anterior. Fiber lengths and angles of pennation were quantified using ultrasound imaging. Neither fiber lengths nor angles of pennation were found to differ between the isometric reference contractions and any of the force-enhanced or force-depressed conditions. Therefore, we rejected our hypothesis and concluded that differences in fiber lengths or angles of pennation do not contribute to the observed force enhancement/depression in human tibialis anterior, and speculate that this result is likely true for other muscles too.
肌肉拉伸后的力量增强以及肌肉缩短后的力量减弱是骨骼肌收缩被广泛认可的特性。然而，导致力量增强/减弱的因素仍存在争议。除了纤维或肌小节水平的因素外，纤维长度和羽状角会影响整块肌肉在随意等长收缩时的力量。因此，我们推测力量增强/减弱状态与参照状态之间的纤维长度和羽状角差异可能导致随意收缩时的力量增强/减弱。本研究的目的是验证这一假设。12名受试者参与了本研究，并测量了人胫骨前肌的力量增强/减弱情况。使用超声成像对纤维长度和羽状角进行量化。结果发现，等长参照收缩与任何力量增强或力量减弱状态之间，纤维长度和羽状角均无差异。因此，我们拒绝了我们的假设，并得出结论：纤维长度或羽状角的差异不会导致人胫骨前肌中观察到的力量增强/减弱，并且推测这一结果可能也适用于其他肌肉。
