Sousa F, Ishikawa M, Vilas-Boas J P, Komi P V
Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, 40014 Jyväskylä, Finland.
J Appl Physiol (1985). 2007 Jan;102(1):382-9. doi: 10.1152/japplphysiol.00274.2006. Epub 2006 Oct 26.
The present study was designed to examine fascicle-tendon interaction in the synergistic medial gastrocnemius (MG) and soleus (Sol) muscles during drop jumps (DJ) performed from different drop heights (DH). Eight subjects performed unilateral DJ with maximal rebounds on a sledge apparatus from different DH. During the exercises, fascicle lengths (using ultrasonography) and electromyographic activities were recorded. The results showed that the fascicles of the MG and Sol muscles behaved differently during the contact phase, but the whole muscle-tendon unit and its tendinous tissue lengthened before shortening in both muscles. The Sol fascicles also lengthened before shortening during the ground contact in all conditions. During the braking phase, the Sol activation increased with increasing DH. However, the amplitude of Sol fascicle lengthening was not dependent on DH during the same phase. In the MG muscle, the fascicles primarily shortened during the braking phase in the lower DH condition. However, in the higher DH conditions, the MG fascicles either behaved isometrically or were lengthened during the braking phase. These results suggest that the fascicles of synergistic muscles (MG and Sol) can behave differently during DJ and that, with increasing DH, there may be specific length change patterns of the fascicles of MG but not of Sol.
本研究旨在探讨在不同高度下落的下落跳（DJ）过程中，协同作用的内侧腓肠肌（MG）和比目鱼肌（Sol）的肌束-肌腱相互作用。八名受试者在雪橇装置上从不同下落高度进行单侧下落跳并进行最大程度的反弹。在运动过程中，记录肌束长度（使用超声检查）和肌电图活动。结果表明，MG和Sol肌肉的肌束在接触阶段表现不同，但整个肌肉-肌腱单元及其腱组织在两块肌肉中均先延长后缩短。在所有情况下，Sol肌束在地面接触期间也先延长后缩短。在制动阶段，Sol的激活随着下落高度的增加而增加。然而，在同一阶段，Sol肌束延长的幅度并不依赖于下落高度。在MG肌肉中，在较低下落高度条件下，肌束在制动阶段主要缩短。然而，在较高下落高度条件下，MG肌束在制动阶段要么表现为等长收缩，要么延长。这些结果表明，协同肌肉（MG和Sol）的肌束在下落跳过程中可能表现不同，并且随着下落高度的增加，MG肌束可能存在特定的长度变化模式，而Sol肌束则不然。
