Konrad Andreas, Tilp Markus
Graz University, Austria.
Graz University, Austria.
Clin Biomech (Bristol). 2014 Jun;29(6):636-42. doi: 10.1016/j.clinbiomech.2014.04.013. Epub 2014 May 10.
It is known that static stretching is an appropriate means of increasing the range of motion, but information in the literature about the mechanical adaptation of the muscle-tendon unit is scarce. Therefore, the purpose of this study was to investigate the influence of a six-week static stretching training program on the structural and functional parameters of the human gastrocnemius medialis muscle and the Achilles tendon.
A total of 49 volunteers were randomly assigned into static stretching and control groups. Before and following the stretching intervention, we determined the maximum dorsiflexion range of motion with the corresponding fascicle length and pennation angle. Passive resistive torque and maximum voluntary contraction were measured with a dynamometer. Muscle-tendon junction displacement allowed us to determine the length changes in tendon and muscle, and hence to calculate stiffness. Fascicle length, pennation angle, and muscle tendon junction displacement were measured with ultrasound.
Mean range of motion increased significantly from 30.9 (5.3) to 36.3 (6.1) in the intervention group, but other functional (passive resistive torque, maximum voluntary contraction) and structural (fascicle length, pennation angle, muscle stiffness, tendon stiffness) parameters were unaltered.
The increased range of motion could not be explained by the structural changes in the muscle-tendon unit, and was likely due to increased stretch tolerance possibly due to adaptations of nociceptive nerve endings.
众所周知，静态拉伸是增加关节活动范围的一种合适方法，但文献中关于肌腱单位机械适应性的信息却很少。因此，本研究的目的是调查为期六周的静态拉伸训练计划对人内侧腓肠肌和跟腱的结构和功能参数的影响。
总共49名志愿者被随机分为静态拉伸组和对照组。在拉伸干预前后，我们测定了相应肌束长度和羽状角时的最大背屈活动范围。用测力计测量被动阻力矩和最大自主收缩。肌腱结合处的位移使我们能够确定肌腱和肌肉的长度变化，从而计算出刚度。用超声测量肌束长度、羽状角和肌腱结合处的位移。
干预组的平均活动范围从30.9（5.3）显著增加到36.3（6.1），但其他功能（被动阻力矩、最大自主收缩）和结构（肌束长度、羽状角、肌肉刚度、肌腱刚度）参数未改变。
活动范围的增加无法用肌腱单位的结构变化来解释，可能是由于伤害性神经末梢的适应性变化导致拉伸耐受性增加所致。
