Ohta Yoichi
Faculty of Health and Medical Sciences, Department of Sports and Health Sciences, Aichi Shukutoku University, Aichi, Japan.
Acta Bioeng Biomech. 2012;14(4):45-52.
The aim of this study was to clarify the effects of tendinous tissue properties on origin of greater force output at short inter-pulse intervals in the 2-pulse trains compared to those at longer inter-pulse intervals. Thus, this study investigated the contributions of the second stimulus (C2) in 2-pulse trains with different inter-pulse intervals on the torque response and tendinous tissue properties of human skeletal muscle in vivo. The torque response and tendinous tissue elongation following single pulses and 2-pulse trains at different inter-pulse intervals (5, 10, 20, 30, 40, 50, 80, 100, 150, and 200 ms) were recorded in the tibialis anterior muscle using real-time ultrasonography. C2 with inter-pulse intervals of 5-100 ms invoked significantly greater torque responses than single pulses. In contrast, the elongation and compliance of tendinous tissue for C2 with inter-pulse intervals from 5-80 ms were significantly lower than those of the single-pulse response. A significant negative relationship between torque response and tendinous tissue compliance was observed in C2 with different inter-pulse intervals. The torque response as a result of C2 is greater at short inter-pulse intervals in which the force summation due to second stimulus coincides with the period of decreased tendinous tissue compliance due to the first stimulus.
本研究的目的是阐明肌腱组织特性对两脉冲串中短脉冲间隔时比长脉冲间隔时更大力量输出起点的影响。因此,本研究调查了不同脉冲间隔的两脉冲串中第二个刺激(C2)对人体骨骼肌体内扭矩反应和肌腱组织特性的作用。使用实时超声记录了在不同脉冲间隔(5、10、20、30、40、50、80、100、150和200毫秒)下单脉冲和两脉冲串后的扭矩反应和肌腱组织伸长情况。脉冲间隔为5 - 100毫秒的C2引发的扭矩反应明显大于单脉冲。相比之下,脉冲间隔为5 - 80毫秒的C2的肌腱组织伸长和顺应性明显低于单脉冲反应。在不同脉冲间隔的C2中,观察到扭矩反应与肌腱组织顺应性之间存在显著的负相关关系。在短脉冲间隔时,由于第二个刺激引起的力量总和与由于第一个刺激导致的肌腱组织顺应性降低的时期相吻合,C2产生的扭矩反应更大。