Maganaris C N, Baltzopoulos V
Biomechanics Research Group, Manchester Metropolitan University, Alsager, UK.
Eur J Appl Physiol Occup Physiol. 1999 Feb;79(3):294-7. doi: 10.1007/s004210050510.
The aim of this study was to assess the predictability of in vivo, ultrasound-based changes in human tibialis anterior (TA) pennation angle from rest to maximum isometric dorsiflexion (MVC) using a planimetric model assuming constant thickness between aponeuroses and straight muscle fibres. Sagittal sonographs of TA were taken in six males at ankle angles of -15 degrees (dorsiflexion direction), 0 degrees (neutral position), + 15 (plantarflexion direction) and + 30 degrees both at rest and during dorsiflexor MVC trials performed on an isokinetic dynamometer. At all four ankle angles scans were taken from the TA proximal, central and distal regions. TA architecture did not differ (P > 0.05) neither between its two unipennate parts nor along the scanned regions over its length at a given ankle angle and state of contraction. Comparing MVC with rest at any given ankle angle, pennation angle was larger (62-71%, P < 0.01), fibre length smaller (37-40%, P < 0.01) and muscle thickness unchanged (P > 0.05). The model used estimated accurately (P > 0.05) changes in TA pennation angle occurring in the transition from rest to MVC and therefore its use is encouraged for estimating the isometric TA ankle moment and force generating capacity using musculoskeletal modelling.
本研究的目的是使用一个假定腱膜和直肌纤维之间厚度恒定的平面模型，评估从静息状态到最大等长背屈（MVC）时，基于超声测量的人体胫骨前肌（TA）羽状角的体内变化的可预测性。对6名男性在-15度（背屈方向）、0度（中立位）、+15度（跖屈方向）和+30度的踝关节角度下，分别在静息状态以及在等速测力计上进行背屈肌MVC试验期间，获取TA的矢状面超声图像。在所有四个踝关节角度下，均从TA的近端、中部和远端区域进行扫描。在给定的踝关节角度和收缩状态下，TA的结构在其两个单羽状部分之间以及沿其长度的扫描区域均无差异（P>0.05）。在任何给定的踝关节角度下，将MVC与静息状态进行比较，羽状角更大（62 - 71%，P<0.01），纤维长度更小（37 - 40%，P<0.01），而肌肉厚度无变化（P>0.05）。所使用的模型准确地估计了（P>0.05）从静息状态到MVC转变过程中TA羽状角的变化，因此鼓励使用该模型通过肌肉骨骼建模来估计等长TA踝关节力矩和力产生能力。
